I've not used Sedo for a long time but bought 2 domains through them last month. (Last resort. tried everything else to contact the sellers)
The website seems a lot better than it used to be but i can't say the same for the service. Seems to be the same slow/poor response from customer services. Especially once they have your money. I'm still waiting for the domains to be transferred.
As for selling, moving away from Sedo was one of the best business decisions I've ever made. I do believe however that if you domains are good enough, people will find them no matter where/how they are listed for sale.