I really enjoy messing around with the blink ability. It's a breeze to zip across rooftops and stay out of the enemy's line of sight with it. Also I like that you can pretty much use it infinitely.  
 
I haven't really gotten to try any of the other ones out much though. Possession looks like it could come in handy, and Dark Vision is useful but not really that interesting. Bending time also looks like a fun skill but I doubt I'll get much use out of it since I'm trying to play stealthily. 

I just finished the game playing stealthily only killed like 14 guys the entire time. Blink and dark vision are key, possession is also very useful if you plan on trying to kill as few people as possible. Also would really recommend you get at least the first level of bending time, its not key but there were a few parts that would of taken noticeably more time without it. Pun not intended

I started off not killing dudes but I didn't like how slow I was while doing it. Typically I play aggressive stealth in these types of games so I got the bodies turn to ash skill and I'm really digging it. I do quick stealth kills and move, leaving no body behind.

I'm rolling deep with killing in mind, I've buffed my health to level 2, turned stealth kills to ashes, and gotten enhanced vision. I'm looking to go further down that route and have all bodies turn to ashes and probably get time bend...

@Dizzyhippos said:

I just finished the game playing stealthily only killed like 14 guys the entire time. Blink and dark vision are key, possession is also very useful if you plan on trying to kill as few people as possible. Also would really recommend you get at least the first level of bending time, its not key but there were a few parts that would of taken noticeably more time without it. Pun not intended

How long did it take you to finish the game?

I maxed out Blink as soon as I could and I just increased my jump height. I want to stay mobile and fast but I also like killing dudes so I'll probably get the turn dudes to ash ability.

@Colourful_Hippie: That ends up being really helpful even just the stealth kills one, but the upgraded version is convenient to have.

I went in maxing blink and mobility, seeing as those two seem to be extremely resourceful for vertical movement. Hell, if you just get the mobility upgrades, you almost never have to use blink.

I only maxed out Blink and Agility and didn't bother with Dark Vision (leaning around corners seemed good enough) or the rest. Went through the whole game only killing a few people.

I prefer more....confrontational means. Bend Time plus the blink and a whole lot of countering and bullets to the brain.

Guess I'm the odd one out.

@huntad: @FancySoapsMan: Ya took like 11 hours playing straight threw, but I almost always finish games under the time most people take, figure add 3-4 for what a normal playtime would be