Not a fan of Grey/Silver either. They both just came off as being really selfish about the whole thing. Silver always came off as being a spoiled brat to me, so I don't know if it's the ship itself or my dislike of the character(s).
Gray/Silver was one I just gradually began to dislike over time due to preferring Gray/Millie personally. Their relationship was much more fleshed out versus Gray/Silver since she died so soon, and I think it was said somewhere in StarClan Graystripe would choose Millie which made me happy.
But the more I think about it, the idea of cats having to choose between cats in StarClan is so ridiculous… couldn't they all just be mates together and be one big happy family and love one another the same, or is polygamy taboo up there too or something?