I bought mine on ebay also, from "citymufflerandperformance". They were great to deal with and got it shipped out fast. It was also $100 less than I could buy it locally. Got it last week, hooked it up, and was able to program my truck. Got an error code the first time I tried it, followed the instructions in the manual that came with it to pull a couple of fuses to reset the computer, and then it worked just fine.
Haven't dyno'ed it yet, but I must admit that I don't think I'm getting 70hp/140ftlb torque on the top setting like they claim. It did make a noticable improvement though, enough that my truck feels closer to the way that it did when I had the stock tires on it instead of the 315's. The speedometer adjustment works great... seems to be accurate. Code scanner is a plus too. Haven't driven enough yet to calculate whether I gained any fuel economy.
If not for the speedo correction and the code scanning capability I would say that the power gain is questionable for the money. But all things considered, I think it was worth the under $300 that it cost me.