I like mine as well. If your not interested in hearing your engine, then I wouldn't suggest getting one. But I love the way it makes it sound. Would sound even better if I could convince the wife to get a set of the magna-flows. As for power gains, I can tell a difference between the two. It's not going to throw you back in your seat, but I went from driving with one for about 9 months, to just recently taking it off for some warranty work. I couldn't wait to put it back on. The car felt like a slug under acceleration.
However, if you are looking for performance, then I'd consider saving up for the X-cal 2. Most ppl will say it is the best bang for your buck. I'd really like to get one, but I've not been able to convince myself that messing with the PCM of the car is good in the long run.