Drew, have you considered just going Boot Camp with Windows 7? You have a fancy new machine already, why not just go the Windows route on that one? Minecraft probably does play better through Windows. Maybe. I don't have stats to back that up, but the game is known wide and far to be terribly coded from the very beginning, so I'm guessing the Mac port is likely more glitchy. Maybe?
With MagicLauncher and OptiFine I'm still pretty happy on the Mac side, but I would be curious to see what you find if you decide to go the Boot Camp route.
So it goes.