for meph i like my orb sorc alot better, just keep moving and shooting orbs into him, i kill meph twice as fast with orb than i do with blizzard, and i find it more reliable. when i cast the blizzard with my blizz sorc vs orb with orb sorc, i see way more damage come off meph when orb goes through than when (and IF) blizzard hits him..
this is with maxed synergies and everything and the same +11 skills