Xerneas is definitely no new Kyogre, no way. It doesn't get crazy special attack + an automatic 1.5 boost to an already powerful STAB Surf/Hydro PumpWater Spout [i]and[/i] 100% accuracy for Thunder. Plus Ice Beam, which deals with a ton of things in Ubers, considering all the Dragon types up there. Even with the nerf weather moves got, he still kicks ass.

I've never had trouble with Xerneas, even in random battles with my OU team. Yveltal's more troublesome with its signature move actually, since, yeah, hello recovery.