Juggs is the guy who shows up in your favorite character's comic, beats the hell out of them, then leaves. (paraphrased from something longpig told me months ago).
Mind you, that's classic Juggs, not current (who is decidely less badass), but I still think he hardly ever jobs. He beats who he should, and only occasionally jobs to the X-Men because he needs to.
Gladiator, on the other hand, should be a force but rarely is. And his mythical battle with Ego the Living Planet, if memory serves, isn't even canon. That said, I don't have a clue if he actually has one decent feat to his name other than trading blows with Thor a couple times.
Yeah, his fights with Ego and Surfer aren't canon.
He mainly gets jobbed out when he appears in X-Men titles. Losing to Thor is definately nothing to be ashamed of (ok, losing to Masterson Thor was because the fight was written terribly), but Thor's never had an easy time with Glads.
A fair bit actually. Gladiator's so notoriously known for his low showings, people don't seem to realise he has a just as many good showings.
He's beat down Binary, Hyperion, Nova, Wonder Man and the Fantastic Four. Gone toe to toe with Supreme, Thor (and beat him easily once), Rom, a Uni-Powered Invisible Woman, Black Bolt and Quasar. He had one of the better showings against Tyrant. Plus he's got some really good Durabilty, Speed and Strength showings aswell.
Check out the Gladiator Respect Thread (link in my sig). You'll see he's more than just a jobber.