I used to have a Skoreit! account that I played on from time to time. There seems to be some real strategy involved in winning consistently. Lifetime I was ahead slightly when I had them close my account.
The biggest concern that I had was the lack of an independent audit. I.e. there was no way to guarantee that you weren't bidding against a house robot that had unlimited bids to burn, just to run up the price and make you burn up your bids.
Just me, but I would stay away. Even being up lifetime, I don't think I'll ever start using the penny auction sites again. It just feels like a setup.