It's good. It's very good.
I'm playing on 'classic' difficulty, which is damned hard and kicking my ass. Lots and lots of saving and restarting missions. I'm trying to get through without losing people, I spent hours just getting through a handful of missions with no casualties.
You will curse the heavens when your inept and frail human troops completely miss targets right in front of them, and are then vaporized by the aliens on their turn.
You will also curse when your frail and weak human, panicked at the carnage around her, accidentally empties a clip into the squaddie right next to her.
There is an 'ironman' mode that does not allow you to reload saved games and autosaves for you, but I'm far to weak to attempt.
From what I can gather you can complete the missions far faster and with low casualties by using lots of 'explosives' (grenades, bazookas) but blowing up the aliens doesn't leave much wreckage for you to salvage for upgrades. A tradeoff if you will.
Anyway its super fun, and super engrossing. GET IT.