There's a couple of things that I like about it:
The dice. I was going to go over all of the cool things about how the dice pool is built, difficulty levels set, etc. but there's just so much I like about the whole mechanic I'd basically be spelling out the rules. Basically though, you can fail at a task yet gain some sort of advantage to help with the current situation, likewise you can succeed but end up with threats that need to be dealt with.
In combat the rolls for 'hitting' and 'damage' are handled in a single roll. A weapon's damage is predefined with extra success rolls causing extra damage. PCs also have both a Wound and a Strain threshold, each working a bit differently. The PCs in the game that I'm running IRL have yet to actually kill anyone, instead using Stun settings on their weapons (causing Strain damage) to disable people instead.
PCs don't 'level up' and instead increase their skill ranks and purchase new talents with their earned XP.
I don't know, it's just a neat system that I didn't fully appreciate when I started playing it here (hat tip to falryx) but am liking more and more as time goes on.
