refering to the gai vs kakashi thing.

i doubt either of them are going all out to the point where they're willing to use their most powerful jutsu. i mean, they're rivals, but there's a spark of mutual respect and friendship underneath it all (if not, one of them would certainly be dead). Also, keep in mind when compairing them that Kakashi is a brilliant strategist. It may be that Gai is much stronger in terms of brute force, but if he opened all his gates he'd just hit a shadow clone of Kakashi, or at the last second Kakashi would replace his body with something else.

Gai missed it when Gaara replaced his body while in the Lotus.

I don't know who'd win in a real fight, and no one will know unless we actaully see them fight each other to the death, but there's more to being a great ninja than pure power.

And about Gai jumping in. I agree with what a bunch of other poeple have said. Lee wanted to do it on his own, and if Gai had jumped in he would've undermined his trust in his pupil. Kakashi says he doesn't knwo if he wouldn't have done the same thing with Naruto or Sasuke. Sometimes you need to let poeple make mistakes so they can learn.

(maybe Lee will learn to be more cautious with his attacks or to wait for the proper moment, instead of just going all out from the beginning.)