I got this on my truck as well. i have been using it for about 5 month now. Easy install. I'm using the gauge pillar through bully dog, and it looks good inside the cab. It has 4 gauges that it can display at once. lots of other vehicle specific settings that can be changed on it. As far as performance goes i did notice a boost in performance. definitely quicker in acceleration. as far as gas millage goes i didn't notice a considerable gain. i installed this on my truck about 2 weeks after i put a CAI and throttle body spacer on, which all work well together. I was getting about 14-16 city/subbern driving, depending on my throttle control (its so nice to really step on it and annoy the people next to me at red lights), and about 16 on long drives. Highway i can get 18-20. I also have a borla exhaust system on now. which i havn't noticed much more gas millage gains since then. (now since i have the borla exhaust on i really like to step on it more, such a nice low loud throaty sound.)
Overall for the price it wasn't bad ($400) compared to 500-600 for the others. performance was increased, and gas millage was a very slight increase.