I guess the whole Vincent/Mary relationship was one of the main reasons I didn't care for GF3. I know a lot of you will probably disagree with me but it seems like they took the easy way out by creating the Vincent character in the first place. Since all of us who have read the novel know Lucy (Vincent's mother) never had a child by Sonny.
With Vincent and Mary you couldn't detect any kind of chemistry, say like there was between Michael and Appolonia, you know,"the thunderbolt" kind of passion.