Only thing I do not like is the amount of additional enemies they throw at you based on mission type, sometimes it feels like cheap/bad attempts at balancing against stuff you could have.
First exalt mission, first turn, second of four soldiers moved, 6 exalts instantly appear in front of my squad and over the course of the next ~5 rounds a total of 8 more enemies spawned in (drop in -> overwatch).
I don't mind hard, but this (and some other instances - 4 crysalids, 6 zombies & 2 thinmen on screen in early game, when lasers have not been researched yet, for example) makes this actually feel more like one of those fixed-layout tactical puzzle solving games rather then a strategy game.
The missions I played thus far where about 50/50 "normal" experience/unbalanced clusterfuck. Going to continue even more carefully, but this is starting to feel just dumb, considering I am playing on "normal" and have sunk ~150 hrs into vanilla..
All the additions, maps, classes, gadgets and most mission types are great additions though, even if they do feel thrown in at strange intervals/clusters (more "things happend and now THIS" rather than "Through research we found ..") - I know that this is going to be an even greater game than vanilla - once I found a workaround for those kinds of situations.