c-cex is unprofessional in my experience. had coins locked up there for weeks while nobody responded to my support requests. sounds familiar? limited experience with bleu but it was good in my few trades.
I haven't had any issues with c-cex so far, thus I cannot report on that. But my experience up to date with trading there was rather ok. They do not have big volumes, I think I only saw once a coin reaching more than 500 BTC of volume (and it could have been fabricated), but a solid double digit BTC volume, yes. It is a small to medium size exchange, and as every such of that kind (Comkort, Yobit.net) it is making its living by accepting new coins faster than the bigger exchanges would do, hoping to get some profit from that. And some of these coins may have caused issues for sure. but still I think it would be good to have ZEIT there.