Let's see, I've used Poison Ivy, Fly, XTC Plus, and Hi-Vee.
I found the 11.5 or 11.7mm ropes are just right for me. Not too skinny, but not too fat. (Though I don't have any objection to a good hank of hi-vee. It's all I climbed on for a few years and I loved it, and still do)