Whats more impressive.To KO or sweep and win every round?

It depends...a fighter that wins every single round against a fighter he was expected to win every round against isn't impressive at all...Mayweather vs JMM and Baldomir are perfect examples. But if a guy wins every round against a guy in a fight in which he is expected to lose, then, yeah, that can be more impressive than a KO at times...Hopkins-Pavlik is a perfect example of that...

...but all in all, nothing beats a KO, especially when the guy who scored the KO wasn't expected to win...Tarver-Hopkins 2, Donaire-Darchiniyan...

 

A knockout. Decisions are left up to criminal judges, such Paul Williams' judges did for him when Martinez beat his arse and when Cintron was going to knock him out. Now Williams wants to go down to 147, well, Cintron will fight him at 147 or any weight.

I like knockouts like the Klitschkos do. Klitschko win every round, then still go ahead and knock their opponents out. Extremely impressive. Why do you think Void's fans had the Klitschkos so much?

 

This question is like comparing a perfect game in bowling and a hole-in-one in golf. Both requires skill but in bowling you have to score 12 strikes while in an ace in golf is only one shot. The element of luck in a hole-in-one higher than a perfect game. In that context, a 12 round schooling is more impressive than a KO. But, in boxing anything can happen the longer it takes, especially if your opponent is a big hitter. Remember Sasakul was schooling Pacman, then one good shot and he was out.
Chatchai Sasakul: Manny Pacquiao!!! One good punch from him and I was out. He has very heavy hands

 

Try and look at the question as a personal preference between the two options.Regardless of opponents.

In general...