Yeah, but tabuu alwways teleports and moves too quickly for me to actually hit it with Rock Smash. So whenever I get up to him, I normally swap over to squirtle who has fast aerials and good air movement speed.
Oh and I've finished it on Very Hard, just not Intense.
Saw your post about the Boss mode of Brawl; I've completed it on Intense using Pokemon Trainer's Charizard exclusively. Just spam Rock Smash for massive damage, dodge when needed. It's still very hard, but it works.