Originally Posted by cslone
Sigh.
Actually, in terms of accuracy it's:
Powertap= 1.5%
Ergomo=2.0%
SRM=2.5% for Pro and 5% for Amateur.
So, to answer the question, it appears that the Powertap is the best PM for the money.
Its manufacturer's claimed accuracy. But honestly, as long as the power readings are consistent,accuracy doesn't matter too much.