I've had this for around 1000km now. Aside from a very brief issue where it wouldn't connect (took battery out and replaced) it has been good. Much cheaper than alternatives, and although it is single sided only, it's interesting to have consistent data for training purposes (or just the fun of having more numbers to look at). Installation was easy (using a SRAM online tutorial) although make sure you have a long hex wrench as the torque required to remove the crank arm is high.

Once eventually installed, this does represent a low cost option to provide a consistent power measurement, suitable for informing training etc. I don't use any other power measurement equipment so I cannot speak to absolute accuracy, but the consistency is key for use training and monitoring progress. The first unit sent was defective and was giving incorrect readings (when it did read). Jordan at Sigma responded to my email promptly and helped to sort out a warranty replacement with minimal fuss.