Yeah, I have two of those 266xl's, and I'm not really impressed with them at all... I avoid using them if I can. Sometimes that means that I don't do any compression while tracking...
I also have a 166, but I don't like it that much either. Partly because you can't set the attack and release, but also because it dose have a kind of 'dark' sound to it that was mentioned before. Can work nice for some things though...