One of the mechanics I really like is how when you kill all active enemies, your marines automatically reload their weapons and have their action points restored to full. Also, when you run into a new group, everyone immediately goes back to full action points. Running into a new group with your last soldier was the #1 way things went south in xcom, and not having to worry about it speeds up a lot of the busy work of moving across the map.
But on the downside, the game is starting to feel repetitive much faster than these games usually do. It also doesn't help that, even playing on Brutal, it's rare that I run into a mission that even feels dangerous. Some of the early fights were more difficult, though more in a worn down through attrition kind of way then in a tense, exciting battles kind of way.
