Sun Fac
They both dispel at the same rate on their primary on AI. Sun Fac taunts turn 1, uses its special turn 2 then fires with primary turn 3. Whereas GQJ dispels as soon as needed and has an equivalent cool down. However everytime you hit Sun Fac you get a 50% chance to get a counter which dispels. So with all the aoe in arena you can get multiple dispels and critical chance downs per turn. Sun Fac taunts and has on average double the HP of QGJ and self heals on its primary. It's a beast :)
Why do you normally see it with Rex? People stun Fun Sac and Rex gives tenacity up turning it into an unstoppable self healing beast..
It's too slow? Mine runs at 195 speed so is not as fast as QGJ can go but OK. Don't waste effort on tenacity mods, even at 97% tenacity it gets stunned... Like any toon..