Tldr; A good game with many great features and fun gameplay. However towards the end a lack of variation, and constant repetitive incursions ruins the end (I havn't actually completed it). Worth the time, but prepare for a frustrating end.
This could been a five star game; fun gameplay, passable story, good combat, good research and manufacturing. I would of liked to have base building and more control over Aerial combat but I suppose we can't have everything. However once you get about 2/3 - 3/4 of the way through the game it becomes very very monotonous, you get attacked by the same aliens, using the same tactics (none), with the same weapons. You defend using the same characters, with the same tactics with the same weapons.
The game reaches a point where you have conquered everything and researched (nearly everything), and you have to wait days (real time-hours) to complete story based research or have some time trigger to occur. All the while fighting off repetitive alien incursions.
This is a very fun game, and it is awesome seeing your raw recruits become highly trained, specialised soldiers (booting up a mission and letting your dual wielding stalker/commando take out a map on his own is great). It is just so frustrating and boring towards the end.