Not sure I've ever seen a game people totally love or love to hate like Rage. I really liked it and would recommend it as a purchase. In most games I'm not a fan of the shotgun usually but Rage has the best shotgun I've ever used and the Pop Rockets are one of the coolest forms of ammo out there.
It had just enough scavenging/side quests to keep me interested and the driving was really responsive and fun also. The gadgets and engineering really made things interesting also.
I was shocked when it was 3 discs but after seeing it and how well it looks and responds I was cool with it. I heard the re-sale value isn't that high so if you can get it on ebay for $25-$30 I'd snag it. Pretty sure there is some serious DLC coming for it.