IBike?

I borrowed one from Kaufman at the bike shop.  I found it to be pretty useless, just because it could never take an accurate power reading due to the rough riding surfaces.  The minute I got on a chip-seal road the power reading blanked out.

In addition, you have to mount it perfectly.  If it is rotated at all, your power numbers are skewed.  I never could seem to keep it stable.

Pretty unfortunate, because I think it is accurate.  If only I could keep it stable...

See this thread.

http://forum.slowtwitch.com/gforum.cgi?post=2500729

There are other good posts on ST about iBike, most are similar.  majority don't like it or don't think it's accurate and a few that really like it and say it is as accurate as anything else out there.