Let's do some basic math here first, to settle any disputes about my rune preference.
Starting with HP quints gives you +76 HP at spawn. Now, let's factor this with Vladimir's passive. For every 40 Health, he gains 1 AP. So this gives us 1 AP, due to the fact that we're shy of 4 HP. Now, if we do this with the Ability Power quints and Glyphs, then we can get 24 AP coming right out of spawn with no items. So, Vladimir's passive grants 1.8 bonus health per 1 AP he has. Queue the calculator. This totals up to a whopping 43.2 extra health, and 24 extra AP. Which means you can survive longer in lane from your Transfusion, and deal more damage in opposition to a HP Quint Vladimir.
With Magic Penetration marks, this adds penetration (lol), which essentially means more damage. Don't get too happy about all this penetration though, otherwise you're going to start ruining (IMO) Vladimir, and completely miss out on what he is truly capable of doing: nuking.
I take a variation of 2 different sets of 9 seals to give me a universal advantage, depending on the team I'm facing.
Armor Seals- If the team has a few AD champions, but not too many. MR Seals aren't good to counter AP teams.
Health Seals- If you want a really strong progressive game, permitting you to harass a bit more.
This is where the debate really comes in. You can take Cooldown Reduction to make your early pre-9 game stronger, but you penalize yourself seriously with a loss of 9 AP. Additionally, this increases your base Vitality (health) due to your passive. Because of this, you start with an extra 16 Health. This may not seem like a good investment, but this gets that extra bit of damage and that extra SpellVamp (from Transfusion) to keep you alive in those tight 200hp v 100hp scenarios.
Potency gives .99 each throughout all levels
Force gives .17 a level, and at level 6 1.02 (Which surpasses Potency at this point). Additionally at level 18, they reward you with 25.5AP.
Around level 6 you should have some vamp on your hands, or maybe boots depending on the root[sic] you took, but that's about when you really start pushing in the kills with your ult. So, considering if one plays aggressively or not between 1-6, Force might be a better choice for some.
These runes are partially viable since the release of SpellVamp Quints. They provide you with +15 AP at the start, not counting the Glyph bonus. This means you get 27 extra health at spawn due to your passive, once again, not counting the Glyph bonus... They determine how you play your early game, and how successful you are late game based off of that.
These runes are extremely viable when stacked with the SpellVamp mastery in the Utility Tree. This boots you up to an amazing 9% SpellVamp at Level 1. Taking the AP Quintessences gives you a marginal increase in health, and about 9 damage on your Transfusion, but the sustain you can acquire from these is just too good to pass up on. Try em out!
So, let's recap briefly.
This starts you with the following statistical bonuses at level 1.
Passive: Crimson Pact: Every 40 points of bonus health gives Vladimir 1 ability power and every 1 point of ability power gives Vladimir 1.8 bonus health (does not stack with itself).
This essentially IS Vladimir. It's what makes him excel at simultaneously being a mage, and a tank. Maximizing this passive is a must, so building HP is very viable.
Q: Transfusion: Vladimir drains the lifeforce of his target, dealing magic damage and healing himself. (600 Range)
This is your main skill, and how you use it determines if you are good, or bad, with Vladimir.
Transfusion received a recent nerf, which affected the damage late-game, and hurt his late game with a Cooldown nerf.
W: Sanguine Pool: Vladimir sinks into a pool of blood for 2 seconds, becoming untargetable and slowing enemies above him by 40% for 1 second, and deals magic damage over the duration plus heals himself for 12.5% of that amount. (~350 radius)
This is your main escape, initiation, and deflection spell. The more health you have, the more damage it does. Be careful when using this spell, because it does cost 20% of your current health to cast. Much like your Transfusion, this spell separates the good Vladimir players, from the terrible ones.
E: Tides of Blood: Vladimir unleashes a torrent of blood dealing magic damage to nearby enemies.
Each cast gives him an Empowered stack (max 4), increasing his healing and regeneration by 8% per stack for 10 seconds. Additionally, his next tides of Blood deals 25% more damage and costs 50% more health per stack.
This is a great damage spell that increases the regeneration effects on your Transfusion. A Q at four stacks of Tides of Blood will restore the health lost, but also return more. However, be careful when using this spell. You can open yourself up to attacks with it if you use it at the wrong time. This spell also hits stealthed targets, and hits people over the Fog of War. Well timed casts of this can result in a kill.
R: Hemoplague: Vladimir infects the target area with a virulent plague which increases the damage nearby enemies take from all sources by 14% for 5 seconds. After these 5 seconds, infected enemies take magic damage.
Hemoplague is what makes Vladimir such a viable team fighter. Well placed Hemoplague's can hit all 5 targets, which gives EVERYONE on your team increased damage by 14% on all of their spells and attacks. This spell is extremely game-changing if used properly.
Spell Penetration vs Cooldown Reduction
**I updated all of this to make it accurate!**
For this explanation, we will use a Banshee's Veil for said MR, due to it being a common counter-purchase.
Language & Terminology:
CDR= Cooldown Reduction
MP= Magic Penetration
MR= Magic Resistance
1. Percentage magic resistance reduction
2. Flat magic resistance reduction
3. Flat magic penetration
4. Percentage magic penetration
"While sorcerer's shoes are amazing earlygame since you reduce most enemy champion's Magic Resistance to zero with Runes, Masteries + Boots, it falls off once they buy a Banshees Veil, or any magic resistance item, which is too common. They now have 85 MR, but you're only piercing 35 of it. The question is, are you going to buy two more items to counter their ONE? If you have even an IQ of 50, you'll realize the answer is: no.
Now consider it with Cooldown Reduction (Lucidity). Assuming you buy a Void Staff with these boots in this scenario. You start off the game with your same old 15 Magic Penetration, and they still have 35 MR. You do slightly reduced damage early on before they grab any Magic Resistance. 17% to be exact, but the 15% CDR lets you skillspam at a rate of comparable damage output. Now they buy their Banshee's Veil, and you buy your Void Staff. 85-15=70. 49% of 70 is 34. So you're mitigating 15+34= 49 of their Magic Resist, while with Sorcerer's Shoes you were only mitigating 35.
Now let's compare both Boots having a void staff. Sorcerer's Shoes is 20(+9) MPen off the top which immediately cuts their MR down to 56. Factor in the 10% from masteries and 40% from the Void Staff (totaling out to 29+50% due to multiplicative stacking) and they’re left with only 6 MR total). Lucidity results in a remaining 26MR, due to the lack of MP boots. The difference equals out to 20 MR. This may seem very substantial, but keep in mind that with Boots of Lucidity, you can land 17 transfusions in a minute compared to a flat 15 (~117% speed).
Let's do some math.
100 / (100+26) = 79% of Tooltip damage with Sorcerer's Shoes
100 / (100+36) = 73% of Tooltip damage with Ionian Boots of Lucidity
In terms of damage lost off Tooltip, it's a measly 6% difference, in terms of damage lost off of Sorcerer's Shoes damage, it's 7%. You're making that damage back and dishing out more with the 15% CDR. Not to mention the higher their MR, the less effect your Sorcerer's Shoes will have on your damage ouput. If they've got 200 MR the damage difference is something like 1%. Making Ionian Boots of Lucidity a much, much more viable option. Especially post-nerf."
Your Transfusion (Q) is a 4s cooldown at level 9, with no CDR. Assuming you take the 9-0-21 masteries as I specified in this guide, the cooldown on your Q gets bumped down to 3.64 seconds. With the CDR boots, this is bumped down further to a flat 3s cooldown. The difference may seem minimal, but it's extremely useful when you break it down to the core mechanics and you write out the math. I estimate you get somewhere around 5~10 more Q casts per minute in with the CDR boots in comparison to the MP boots. This equates to somewhere around 1,000~3,000 Damage-Per-Minute more.
Furthermore, if you do recall, flat penetration applies before %. This is what most of the argument is based off of. Additionally, utilizing all of your skills properly in the smallest time constraint is a key component of maximizing the benefits of the boots.
The basic logic behind it is: More cooldown= more damage= more kills. Getting the -20 MR shred on your boots doesn't do much once they start to build up, so you need to focus more on percentile in opposition to flats, which is when the Void Staff comes in. Void Staff+ Sorc Shoes provides great, but still less than CDR boots, damage.
If somebody has 250 MR, 20 off of it will only deduct roughly 2~5% of their damage resistance. In this example, you do 450 to the enemy with Sorc Shoes+Void Staff, but only land 5 Q's per 15 second.
You do 435 damage to the enemy with Lucidity+Void Staff, but you land 6 Q's per 15 seconds.
2250 w/ Spell Pen boots
2610 w/ Cooldown boots
This is just a vague example of what would happen, numericals are only approximate (Give or take -15/+15)
The damage increase looks minimal when you look at it with specifically that ONE spell, but it is insanely increased between your two spells, and your ultimate. The 14% amplification makes your damage skyrocket with more cooldown.
Cooldown boots help you sustain longer, & harass more; which is my play style. In team fights, they let you do more casts of everything, making you more useful.
Spell Pen boots help you do good early game damage, sustain less(minions have no MR), and harass slightly less. Team fights, you do a smidgen more damage, but you miss out on that ONE Q that could've killed their Talon, who just killed your Kog'maw.