I havent elaborated that much but using too many pops typically seriously cuts down on the ppc clicks. Popunder and exit pops are pretty harmless but common popups often just pisses people off. Also remember that darkblue often pops its own roar.com search window (and annoyingly which you wont get paid for), so you may end up with even more pops.
Exit pops are the only type where there is pretty much nothing to lose using I think.