I own a Demeter Compulator, and I've never felt the need to use it live. I agree with you, for live music, compression isn't the best thing. Playing dynamics will trump it any time IMO. I've toyed with the idea of selling the Compulator, but I think it'll be useful for recording, so I'm gonna keep it around. If you have more than one compressor, I think you should sell all but which you think is best. It'll free up some extra cash, and you'll still have your favourite compressor on hand if you need it.
Just my 2 pennys worth.
Good luck!