i am a ps3 fanboy, but would still only recommend it as a rent, since i dont like any of the halo games. halo wars is only for people who lke RTS games or are total halo fans who are too blinded by their 360's fumes to know the difference between halo wars and the other ones.(sorry, but some people are truly like that.)
anyway, to step away from the bias, this game isnt a first person shooter like the other ones. the best way to describe halo wars is it's sorta looks like how spore does, aside from building your own characters. you do not play as master cheif, you are multiple groups of soldiers that you tell to move to areas and take them over. it is turn based and slow paced. if youve played civilization, it's like that but without the civility. it's just halo without all of the good gameplay elements that people play halo for. i doubt that many people will like it other than the 360 fanboys who say "OMGZORZ!!! ITS DA H4L00 GAEM!!! IMS DA GOINNA GETS IT CAUZ ITX HALO!!!!!" who only buy it because it's halo.
(sorry is anyone is offended by this, buy i know people who actually act like that...)
one word to describe this game is "liberation" this has many reasons to it. one is that the game is about liberation and two is that this game will liberate anybody who doesnt know what it's about(like some 360 fanboys)
hope it helped.