Actually I like both. If I'm tired physically I will play defense because of its laid back style. But if I really am into it, like after school, I will play offense.
It really depends on what the other team is doing for me. If I see them pushing super hard I'll change my gameplan to defense to help keep them from pushing too far. If they are too defensive I'll switch to offense and help push.
Offense is more fun, but I find that if I'm not playing as medic, I'll score more on the defensive team. If I'm playing as medic, I usually perform best right behind the front line on the offensive side.
defense makes it easier to be a scout : D at such mentioned maps , but even cps like badlands (plz give me it back ill be a good boy!) well and the ctf, i prefer offense
defense is the best because when the offense moves on, you have to rethink everything about your strategy. Specially in dustbowl with 2 points and goldrush with 2 to 4 ^_^
snipers prefer defense, I think, because attacking ain't as easy to do