I loved Thrawn, but wasn't a fan of the Vong. Then again, my knowledge of both is somewhat limited.
I didn't mind the character when he first appeared, but the stuff they later tied to him - namely the Empire of the Hand and all his work to prepare the galaxy for the coming of the Vong - ruined him for me.
I never even knew about that latter stuff. lol From the sounds of it, I should like being ignorant of them.