League of Legends (LoL) Question: What of these ADC's should I buy ?

Since the Marksman Update earlier this season, Riot's done a pretty good job with giving each marksman a unique role, as well as a set of strengths and weaknesses.

-Tristana-
~Strengths and Preferred Role: Tristana’s primary strengths and role lies in pushing and taking objectives. Her abilities allow her to push waves very fast (thanks to the passive on her bombs and the effectiveness of Runaan’s Hurricane in her build path), and her bomb is invaluable at taking turrets quickly. She also has several abilities (Rocket Jump and her Ultimate) that can be used in a pinch to disengage, making her fairly safe.
~Weaknesses: Tristana lacks in damage abilities when looking to fight champions, and has sub-par stats when it comes to dueling. While her abilities can allow and experienced player to fight hard, using the reset on her jump to destroy in a teamfight, most players them for the sake of safety, and focus on the pushing aspect of the game.
~IP Cost: 1350
~On sale for RP this month?: No

- Miss Fortune-
~Strengths and Preferred Role: MF does her best work in a teamfight. Her passive rewards her for attacking different enemies, and her damaging abilities all have some semblance of AOE. She’s best known for her ultimate, which can be game changing when timed and aimed correctly, and supported by friendly CC.
~Weaknesses: MF is not much of a duelist, with her power waning as she attacks the same target. She has some mobility in her W (acting as a speed buff), but no other mobility, meaning she can be focused down fairly easily. She also offers no forms of hard CC, relying on her team-mates to keep her safe and in range.
~IP Cost: 3150
~On sale for RP this month?: No

-Jinx-
~Strengths and Preferred Role: Jinx is generally known as a “hyper-carry”, with a stronger snowball potential than most champions. She has great wave-clear at later levels, and has a strong, if somewhat imprecise ultimate. She excels at dueling and team-fighting, and doesn’t do a bad job with objectives.
~Weaknesses: Though she has several abilities, almost all of her damage in team-fights comes from auto-attacking. So, if not handled properly, her damage output is less than stellar, and fights could be difficult. Like MF, she only has a speed buff as a reliable escape mechanism, so she can likewise be burst down if not properly positioned.
~IP Cost: 6300
~On sale for RP this month?: No

-Lucian-
~Strengths and Preferred Role: Lucian, of this set, is likely the strongest duelist. His passive can trigger between each usage of his abilities, all of which deal damage or assist positioning, and reset themselves with consecutive attacks. His ultimate, like MF’s, can be absolutely devastating, given the right timing and positioning. His dash can cross walls, and he has enough speed to be quite easy to position in a fight.
~Weaknesses: Lucian is not as strong on objectives as the other champions listed here. Additionally, the constant re-positioning and weaving of his passive can give him a higher skill floor than the other champions – Lucian’s abilities must be mastered in addition to his auto-attack usage in order to be effective. Further, Lucian is somewhat short-range, meaning he has to get closer than comfortable to do most of his damage, which puts him at risk.
~IP Cost: 6300
~On sale for RP this month?: Yes

-Varus-
~Strengths and Preferred Role: Varus relies the most on his abilities of all the champions listed here (namely, his Q) to deal most of his damage. That being said, his Q has a fantastic range, and even after bowing out of a fight, you can occasionally help with a stray shot, continuing to have an impact. Further, his ultimate is hard, reliable CC, something somewhat rare in marksmen, which can be used both offensively and defensively.
~Weaknesses: Varus has no real escape, like MF and Jinx, though he doesn’t have a speed buff like the aforementioned pair – he’s most immobile. Varus also has great damage, but it’s somewhat reliant on managing the passive on his W and hitting his abilities, which are all skill-shots of some form. Finally, his abilities are all AOE, making him ill-suited to duels, and locking his influence into long-range teamfighting.
~IP Cost: 4800
~On sale for RP this month?: No

Look into them all based on their differences. If you're willing to wait a bit, you could try the champs when they hit their free-rotation, so you know what you're getting into before you commit. Hope this helps!

1-tristana for mobility, great split pushing, easy to learn
2-mf has a good laning phase, good zoning potential, great team fights if you use her ult with team cc's
3-jinx is strong-ish rn, easy to play, not complicated at all, aoe damage, runs out of mana early if not managed properly
4-Lucain has amazing early game with lvl 2 power spike, great kill potential, can't really be out-dueled by anyone if you use hit kit properly, good at split pushing, sustained damage, mobile with his e
5-varus has good poke if you can land his skill shot, cc on ult for easy kills, zoning potential

hope this answered your question fully. really you just have to play more of them to find what best fits you though...good luck!

i would reccomend miis or jinx :) with good mastery and rune page +build

Hello
I recommend you Miss Fortune or Jinx.

Buy Jinx