my friends did and it's great. I visited them in person and they are very friendly, have a good dyno and lots of cool computer for tuning.
I saw a few greatly tuned cars and if you buy a chip from them and wanna have it dynod, you only pay a 100USD more, they run a dyno before and after the install and they spec. modifiy the ECU for your car. This means even more HP since they will have a car there, they can make the most out of the car.

Too bad, they don't have anything for 96+ V8 BMW engine...

tip: don't buy a ECU from them ask their distributors for pricing, they are usually cheaper ! I had an account and they were offering 20-25% off of their list, but cert. dealers gets as much as 40-45% !!!