They're really different in concept.
GNR is an incredibly in-depth shoot of a single speaker type in a single cab that has a notable moment in its history, for which it's named.
(r)Evolution is 8 cabs, each shot with 2 different speakers. It's also a little bit more recent than GNR, reflecting Ownhammer's continued evolution of their best practices.
Some find GNR to be really special.
Personally, unless you're looking for that specific mojo, I'd go for the more varied (r)Evolution, especially if you don't already have a lot of Ownhammer IRs.
Neither one is that expensive, you could just get both