I've purchased three 32GB 3G iPads from Cowboom.
iPad #1 was in physically great condition, but the screen had some SLIGHT issues. Slight discoloration in certain areas and some backlight issues. However, there were zero scratches on the screen. 1 dead pixel. Barely noticeable. Warranty had expired
iPad #2 was in great shape all around and the screen was in great shape with 1 dead pixel. There was 1 tiny nick on the screen. Warranty expired.
iPad #3 was in overall great shape with one small, fine scratch on the screen that is not visible during use. There may be some burn in on the screen which I find odd, but I can only detect it when facebook is loading. This iPad was never registered, so I was able to register it as new and I have a full one year warranty now.
The prices varied from $220 to $240 plus tax. Overall I've been pleased with them and delighted to have a warranty, but I wouldn't count on being that lucky.
These were all considered condition grade 6 on the web site.