I've only run two, viperROM and Calkulin's, which I'm running now. Both are great in their own ways. I found viperROM to be a bit more stable, and Calkulin's to be better on battery use due to the built in undervolting. You could achieve the same undervolting with viperROM using his script but I never got around to tinkering with it. Both are lightning fast. I'm running Calkulin right now because it has better theme support and viperboy has been busy with the ICS port so he hasn't updated his ROM in a month.
Blazer ROM also looks good but I haven't tried it, and ACS has their own ROM out but it's a bit too themed up for my taste.
Development is undergoing a bit of a transition right now though, as a new base ROM, kernel and modem was just leaked last night. It may be best to wait on flashing a new ROM until the current ones are updated off the new base.