I tip my hat to the creators, because recently happened to me so when I discovered many years ago HoMM II by chance and this typical "Only a train, then I'll stop" - had feeling. The integration of a very complex building strategy with turn-based battles in the SF context succeeded seamlessly and also charges for multiple playthrough of history (I'm just at the 4th pass). Technically XCOM is also mature, with beautiful graphics, devilishly cunning AI on higher difficulty and almost without crashes on my system.
What I particularly liked were the comments of the NPCs in the progress of history, where one notices that a fan of good science fiction behind it ("Quo vadis, Humanitas?").
Conclusion: A very strong buy recommendation on all the Knobler among strategists who enjoy playing turn-based concepts!