God of War has always been a good series. It's got a fairly decent combat system (not the best or deepest, but it's inoffensive and gets the job done), but the real meat is in the level design. There are always some very clever puzzles to figure out, or various challenges, set pieces, and bosses to conquer, and it's all evenly paced to keep from feeling repetitive. And it just has a lot of polish. None of them are very long (usually about 10-15 hours), but they're very "packed," you could say.
God of War III continues all of this well enough. If you haven't played the previous games in the series (which are available for the PS3 in HD), your enjoyment might be hampered, as it begins immediately where GoW2 left off, which might leave you more than a little lost as to what the hell's going on...but then, since there's nothing as epic as
storming Mount Olympus and fighting Poseidon mano-a-mano, so maybe you won't care. The story of the games, in my opinion, is incredibly stupid anyway.