I've had both the original GTech Pro and the newer GTech Competition (since replaced by the SS). I've seen the older Pro for as little as $35; it's a neat toy but as stated above it's better for checking improvements between engine mods. The Competition model is practically a professional-caliber unit which shows RPMs, gives you shift lights if you want them, a full Christmas Tree, records umpty-teen runs on up to four different cars, and lets you download the whole schmear to your PC to track using their included software. Plus the user interface is VASTLY improved on the newer models. If you've got the $$, buy the SS or the model above that. Or borrow one first... if you want something neat but cheap, get the Pro model. It's better than a butt dyno.
I have not yet tried Passport's competitive product.
[RICHR]