I have one, It hasn't been too bad, I cut the cadence cable after a few months because all i really wanted was the miles and the clock. cadence did seem to work just fine though.
The original battery died in about 9 months so I replaced it around xmas and its been working well since, hopefully I'll get longer out of a fresh battery
everything was fine, I believe until the battery started to go, then i noticed my mobile phone would interfere with the counter (it clocked me at 56mph up hill!) as the mobile would receive a text or call, I haven't done any research, but assume that the wireless signal gets corrupted somehow by the mobile signal.
this has not happened since the battery was replaced, and is possibly something all wireless computers are subject to.
would i like a "better" computer, of course. but its cheap and easy to take with me. I'd really like the knog one, but feel I'd leave it on the bike and it would end up stolen.