blizzard: fastest boss runners period.
CL/FO: best pit runners
meteorb: a general build that is a jack of all trades but isn't the best at anything in particular.
there are a bunch of other area runs like the pits, mausoleum and CS comes to mind, that are as good as pit runs. they just have different immunities. if you want to run them, find out what the immunities are, and create a character that has different elements in her attacks.
for meph my fire sorc can tank meph in a couple secs. drop a metor, use a static feild, fire ball, metor , then pump fire balls till the 2nd metor hits and boom he dead i just walk right into him and let him have it he can never kill me before i kill him