AC IV is probably the best game of last gen and this gen and i don't think because it's a launch title that's going to change soon. Until Watchdogs comes out. The reason I say this is because their games seem to capture the best balance between open world, graphics, story and things to do that's actually enjoyable to play.
GTA has really taken a step back and isn't as appealing. Red Dead Redemption was very good. LA Noire had a good story but it's gameplay was a step back.
Square has sleeping dogs and murdered soul suspect coming out but i don't even think that's open world and these games really aren't on the same level.
Infamous second son is coming. Batman but these are superhero games and still don't think they have the same appeal.
Then there is bethesda. The witcher and games like that that are more rpg's. Skyrim and games like fallout are really great but I don't think they have the same fun factor or blend of action and combat and fun that ubisoft are coming up with.
At least in my book. AC IV and Watchdogs are the two games i'm looking forward to and playing most this gen so far.