Installed one just this Saturday. So far so good. Installation was both easier and harder than I expected. I did manage to find a postion for the computer that works with my syntach/carbon stryke aerobar setup along with a profile water bottle, which I was expecting to be tougher. On the other hand, all my bottom bracket tools are too old to work with my newish dura-ace bb, so I took it literally across the street to my LBS to have that installed. The connections are all very stury, they use good heavy gauge wire.

I guess so far my impression is it does what it is supposed to do. The display is pretty nice, I notice I hardly look at the (small) mph readout, which is a big change from my old cateye. The instructions don't really detail the features of the computer too well. For instance, I haven't figured out how to tell it to start a new ride without clearing all the memory, or get the temperature display in fahrenheit. Software is good but they claim they lock it to a single computer, which sort of stinks because I have it installed on my PC but would like to also install it on my laptop for taking to distant races.

I have no way to vouch for accuracy. It updates the display every crank revolution, which means it is not exactly "instant." Seems like it has some amount of hysterisis...as I go through a series of quick rollers the displayed power moves up and down a few seconds behind my perceived exertion. I also notice that as I come off a steep hill coasting and then hammer it in top gear up and over the next little roller, the display will show like 330 watts, which seems a heck of a lot easier than the same 330 watts it was reading on the way up the hill. There are other times when my perceived exertion and the wattage don't seem consistent after an abrupt change in grade, but never for more than say 10 seconds. Hard to know what to believe, I have heard others make similar claims about powertap, etc, so it may be that coming off a short period of coasting it is easy to hit high wattage without meaning to.

Bottom line is I'm pretty happy so far. Gives me the option to use any wheels I want and I can use an FSA crank with it if I chose to, and the cost is much lower than SRM and I think the display is nicer too. For the difference in price you could cover about half the cost of a setup for a second bike. Recommended.