since i've only played Baldur's Gate 2, FF7 and FF9, i'd have to pick BG2. its got more depth and is ad&d based
as for some of the ad&d dm misadventures

i've not had the misfortune to play under a bad dm. any dm that can't improvise no matter what his players do shouldn't be a dm in the first place. players can always be counted on to screw up the best laid plans