I liked RDR. It wasn't fantastic all the way to the end, but at least I finished it. LA Noire on the other hand felt rushed, and I couldn't even finish it before moving on to better games. The facial motion technology they used was very impressive and I hope to see it be applied to more games in the future, but the game itself wasn't good.
R* games lately have been really awful ports though, so either would probably be a technical failure on the PC.