Should have included a poll
I think Cheater is the worse by far.
Quitting is bad but mostly for the so called, "never die warrior" or "willing to die in the ring guy", who usually gets a taste of reality. Do we really have to discuss the deeper issues such as wives, mothers, children, family, money.etc. Thats the real reason most fighters fight.
Knee taking can be and occasionally used for tactical purposes ie. buying time, obviously hurt, gathering oneself. No shame in being smart. Shame on those who view this as shameful.