I'm skpetical though of Rare's ability to make a fun game.
I thought Kameo on the 360 was excellent (completed it twice in a row) and had a sense of fun about it, spoiled only by the underwater sections and relatively short time it takes to complete.
I was very disappointed by Perfect Dark though. It felt like a current generation game and didn't really offer anything new in the gameplay stakes either. It definitely had no fun factor (for me).
So I'm sitting on the fence as far as RARE are concerned, but Viva Pinta does looks interesting.