Considering that with his actual powers Quicksilver can travel from Greece to the U.S.A. and come back in minutes as showed during an Avengers issue, his speed, mixed into the body of a Colossus powered by Mjolnir would grant Colossus serious chances of giving troubles to Thanos, but you gotta consider that Colossus isn't expert in the use of Mjolnir plus he can't use GodForce while Thanos only needs to blast him 2/3 times and then throw him into space.
I give this to Thanos based on experience alone.
Colossus hasn't anywhere near the vast experiences in fighting godlike beings and cosmic forces such as Thanos. He also use's cunning to defeat his opponents. Colossus would be too overwhelmed with this new found might and while having trouble adjusting to it, Thanos would use it to his advantage easily.
I donīt like these speedster-powers. If you think them to their logical end, they make a character near unbeatable in combat.
If you can move at the speed Quicksilver is officially equipt with, you HAVE TO be able to think, use your senses and react at the same speed or you couldnīt act in ANY way. That would mean any other person is virtually standing still while you are at superspeed, ergo no combatskills, HOWEVER superior, would do the other person any good.
Besides, wouldnīt it be the most boring power there is? Imagine, while at superspeed you could run a hundred kilometers in a matter of seconds, but since you have to perceive, think and react at the same speed to coordinate your movements, to your mind it would be like jogging hundred kilometers at normal speed while everything around you is practically not moving at all.
But what am I talking here, LOGICAL thinking about the effects of powers!
My favorite issue of X-factor was the one where Val Cooper orders psych evals for the team after some big mission. In his session, Pietro explains that he's so grumpy all the time because his entire life is like being stuck in line behind the old lady who cant remember how to use the ATM.
- Thanos slagged it out with Warrior Madness Thor w/ Power Gem.
- Took punches and blast from Odin.
- Slugged it out with Hulk, Masterson Thor, Thing, and Herc.
- Pimped slapped both Drax & Hulk
Slugging it out with Thanos is stupid. He'll rip that hammer from Colossus and stomp him. Adamantium? Does that prevent Thanos from headlocking him? Thanos from punching him? Colossus ain't stronger, he'll still get man handled. Speed? Blasting the ground into crater holes would slow Colossus down.