I'be been a member about a year and like any site, it has its good points and bad points. People are friendly and I've found customer service response time to be excellent - usually within a couple hours. There's a variety of contests always going on and they've just started having more and more professional photographers as impartial judges.
As far as the contests go, the worst part is the member judged contests. He who has the most friends wins, regardless of what the pic looks like. One reviewer talked about the points system and how it was spam just to rack up points. To be fair, I recall that reviewer being atop the monthly and weekly points board the whole time they were there. They also had a mega load of groups they created, most of which were redundant. And you earn points for that so yet more easy points for that reviewer and quite hypocritical IMO. I can understand why they changed that rule.
This site is for all types of photographers. I believe if you're truly a professional, you wouldnt be wasting your time at photo sites anyway. I believe the site is more known for the contests and not for selling. There are plenty of other sites for that. I find it's easy to upload and consolidate my pics into albums. The site is easy to maneuver thru. I do not like that they allow minors and have highly sexual adult contests and pics without being able to verify a persons age (like requiring a credit card or driver's license at sign up).
All in all, I've been happy with it. You'll always find someone that doesn't like a particular site and sometimes it's just sour grapes. The only way to know is to try it for yourself.