I am going to go ahead and say it: King of Tokyo is far superior as a light and fun dice game than Quarriors is. I find both games comparable, but one is simply better.
Quarriors would not be so bad if it just didn't over stay its welcome and lacks theme to make up for its drawbacks.
KoT is fun until the very end, has theme in spades.
I really didn't find the two games all that similar. That said, strictly from an enjoyment perspective, I have had a lot more fun with Quarriors, largely because I enjoy the deck building element of gathering creatures and spells. As for theme, Quarriors essentially has a similar theme to games like MTG where the player is a summoner with a range of monsters and abilities to choose from, as my play group are current and ex-MTG players that is a theme that resonated well for us.
Is KoT a superior game? No, just one that appeals to different gamers than Quarriors.