As I reported a while back, I am helping a friend with his first quad and he got one of these.
There were a total of 2 soldering issues. One on each board (Revo and OPLink).
The Revo had a solder bridge on the MainPort filter chip that kept the MainPort from working at all. I fixed it and it works now. He is using MainPort with a $14 eBay GPS. Using the on board (Revo) mags. Calibrated mags with USB (not recommended) and it works fine. Flying in VelocityRoam so he can fly!
The OpLink had a capacitor that looks like it became disconnected during a soldering operation. It worked the way it was, but I resoldered the capacitor and it still works.
Both boards have been flight tested now and they fly fine.
I added a review on ThanksBuyer.com, 3/5 stars because of the two solder issues. The review has not cleared moderation yet. I wouldn't bet on it ever being posted.
I would buy one if I needed one, given the price drop ($50 for the Revo only, $66 for the Revo+OpLink, shipped) and the fact that they were repairable by me. Buy them with PayPal and if they don't work, you can get your money back.