I agree Rare was overhyped towards the end of the N64's lifetime; I didn't enjoy Conker or Banjo-Tooie or Perfect Dark nearly as much as their earlier games, but they did churn out some pretty good games. The DKC series was excellent, though at times annoyingly difficult, Banjo-Kazzoie was fun, Goldeneye set new standards for FPS and Blast Corps was pretty unique. I didn't like Diddy Kong Racing, Donkey Kong 64 or the Killer Instinct series much. Their Gameboy offerings were crap. Seriously, go back and play Donkey Kong Land and tell me it wasn't horribly programmed.
But honestly, the only Rare Cube offerings that I was interested in was Star Fox Adventures and Donkey Kong Racing. And after playing through Star Fox, I won't miss Donkey Kong Racing so much.
Donkey Kong Racing became Saberman Racing. Kameo turned into some refugee from Ferngully. Perfect Dark is now about a cheerleader in a spy suit.
I won't say that Rare is a bad developer. I will say they WERE an incredible game developer, but they lost their way as they focused more on graphics and less on core gameplay. And I doubt Microsoft will help them with that, just as long as Joanna's boobs bounce realisticly. I do hope they do make excellent games again, even if they are on the evil green box.