RATM isn't great. They've got a few songs, but mostly they just are too loud and angry for me, like they're trying too damn hard to rage against that machine.
Superunknown is the best album to come out in a decade, but that doesn't change the fact that Soundgarden's last album was not much to write home about.
Audioslave has had only one album, but I feel safe saying that so far they're up to par with Soundgarden. Their album is totally recommended. Upon giving it enough listens I've concluded that 1-2 songs are worth skipping, and the rest are anywhere from pretty darn good to absolutely superb. I'm glad I actually spent money on it! If all albums were this good people wouldn't have a problem spending money on them. I'd eagerly buy everything instead of DLing MP3s if I knew I had something in the same league with each purchase 🙂