Quick review - It's pretty much the same as the previous Stronghold games, just looks a bit more up to date. If you haven't played Stronghold at all, well it's a nice little game which, unlike other RTS games, allows you to create and maintain your own castle in quite a bit of detail...and either enjoy building and keeping your people happy, or go to war against other AI or human players. It's good fun, and is very focussed and contained which I think makes it more enjoyable than some other sim or RTS games.
The drawbacks - the one player missions and AI opponents won't keep you occupied long, which means you need to play mutliplayer online to really get the most from it...but... this game is really flakey online, often throws you out of a game, which seems to confuse it more until you restart...it can take a while to get into and stay in a game online, but when that works it really is enjoyable. New patch needed I think, then this would be really good.