League of Legends (LoL) Question: Kayn Statistics

I think that Kayn is a very versatile Jungler/Midlaner who can offer different ways to play due to his passive; The darkin Scythe. Personally, I prefere Rhaast Kayn because it fits better in this metagame, the reason is simple, he offers damage and a great amount of lifesteal with each of his abilities but SA can be viable too depending on the comps of both teams (yours and enemies), now im gonna explain pros and cons of Rhaast or SA.

Shadow Assasin Kayn.
Pros;

More mobility with your E (Shadow Step) with slow immunity.
Extra damage to enemy champions with your passive and permanent bonus damage to monsters, making him wave-clear exccelent.
W offers poke and so much damage while you can move to do other stuff.
Chances to do lit combos and delete an objective without taking any damage.
Ultimate resets passive bonus damage.

Cons;

No CC.
No lifesteal or survability at all due to your low resistances.
Is weak VS tanky comps, like Gragas Top, Sejuani Jungler, Braum support.
It´s a bit harder to master than Rhaast Kayn.
Your abilities don´t heal you.

Rhaast Kayn.
Pros;

Hard CC with W.
Huge amount of health regeneration and lifesteal.
Even that he doesn´t have bonus movement speed in his E, he is still very mobile.
Posibility to trap enemies and distract them to offer peel to your ADC/APC
Good against tank comps.
Better if you need a tank in your team, sometimes he seems to be unkillable.

Cons;

Less damage.
W can´t be casted while you are moving.
His wave clear is way worse than with the SA form

Summarizing, I recommend (in my personal opinion) to play Rhaast because is way better in this meta but SA is so good when the enemy comp is full of squishy champs and you have enough tanks in your own comp. ^^

I particularly prefer Kayn as a killer of the shadows, since I like champions more with mobility and lethality. Looks great with deadly marks and attack speed! It works well to kill enemies by walking wild in the jungle and adcarrys that are in the rear. I hope I have responded well. (I used the translator to respond, if you have any spelling errors, copy and paste from English to Portuguese on google).