Shenmue is a RPG, there's really no point comparing
sort of rpg/adventure/fighting game but Prize Gotti said that mgs series are the best series - not shooters or whatever.
I think they're great but not the best. Don't get me wrong, I really like metal gear solid series.
GTA London was a failure but overall GTA series are great, better than mgs.
Tiberian Sun was also good, could be better if it got finished, ea fucked things up, but it was still a good game.
I think mgs2 was also not a great game. I loved first part on psx but mgs2 on ps2 wasn't as good.
Shenmue imo is the best game series ever but not everyone will like it. It involves a deep story. While many reviewers gave it 10/10 and said it's the best game ever, sites like gamespot and some other one gave it 8/10 and they didn't understand what it's all about.
edit: come to think of it it's hard to compare different genres.
Somebody who loves strategy games will love C&C, people who are into fps might say that Half life is the best (imo it's wack) so there's no point comparing on that level.
Definately MGS is the best sneeking/shooting game and it's definately better than Splinter cell.