First up, UFO:AF is NOT an X-Com sequel, but it would be pretty futile to attempt to review it without referring to those games (a lot), if only as common frame of reference with those interested. They do have an awful lot in common. So here goes.
Strategic layer. Different, and somewhat limited. No money management, base building or recruitment - bases and territory are captured rather than constructed. Character development is very good.. effects are (generally) noticeable, and you do start to "care" about your boys (and girls) at least to some extent. R&D is implemented very well... it has a nice logical structure and you have a lot more control than X-Com over the paths your R&D takes. X-Com was pretty much "do everything" - in Aftermath you need to choose, at least in the first half of the game. I like the touch of intercepting UFO's with Eurofighters, MiG 29s and such - adds a nice "Independence Day" feel. Overall though, though things do get more complicated as your territory (and the biomass) increases, the strategic side is pretty much just a framework for the tactical game.
Tactical game. There will be a lot of opinions on this, and personal "tilt" is very important. Totally different from X-Com in any of it's incarnations, and LSN, it's basically a "real-time that stops when anything happens" approach. You have full control to pause and amend orders etc at any time. It actually works very well IMHO. There is an awful lot of tactical subtlety possible that initially you don't appreciate (most comments to the contrary are from those who have only played a few "simple" intro missions), and as the game progresses you need to learn how to apply it to succeed. The interface is easy to use, and easy to customise (turn off the voice sounds asap - unbelievably annoying even if the voice acting had been good - it isn't), and tactical missions flow very smoothly. "Random" or not, they can get a little repetitive, but so did X-Com. Best feature though is the variety of weapons, everything has it's use and it's place - and needs different tactics to use succesfully. Don't overlook some of the early stuff, even as the alien technology becomes available. Worst features are limited AI (this gets propped by "porked up" firepower) and maps which get a little tight.. in the UFOs particularly just orientating your troops correctly can be an (often fatal) annoyance.
Overall. Review scores have been in the mid-high seventies which is probably about right. You'll see a lot worse games scoring higher though. The biggest problem with UFO:AF is the X-Com hang-up on the part of just about everyone, Aftermath isn't as good, but it never could have been as good. You can never top nostalgia.. as UFO:Apocalyse demonstrated. Take UFO:AF on it's own merits, and while it won't have X-Com longevity, you'll get your money's worth and some entertainment until EYSA is released, anyway
