wow. i am like a right brained guy training with power. maybe that's why i'm not as good at this sport as most of you all.

OP - I have a quarq riken and a SRM. I started training with power in late 2007 with a power tap and before that borrowed some power taps to give them a try (they sucked hard - didnt work in the wind, rain, humidity, cold, warm, shade, whatever). With limited wheel choice, I gave up the ptap in winter 2009 and switched to a quarq because a buddy of mine was a dealer and I could get one for about half the price of an SRM.

The quarq worked fine as far as I could tell, but again, considering my right brained tendencies toward training there could have been drift or offset inaccuracies that I wasnt likely to detect. In May of this year, so about 4.5 years later, the quarq started telling me i was doing 3,569 watts for over 5 minutes. I thought wow, I've improved, but after rigorous statistical analysis realized it was a strain gauge issue. Quarq sent me a Riken (no cost) to replace my wonky cinquo, and due to a gxp bb already being in place, I slapped it back on and it works fine. Although my stupid magnet keeps falling off, which is pissing me off.

In the mean time, because I'm doing my best to keep the secondary markt economy moving, and I wanted a pmeter for my TT bike, I bought a used SRM on a DA 7800. I'm hoping to get it assembled this week, and hope i can figger out how to make the fecking magnet stay on.

I'll use a garmin edge 500 for both because I know which buttons to push to get the readouts I want, didnt want to drop another $X for the SRM PC whatever it's called, and didnt want to put another goddam magnet on my bike to get a speed readout on the SRM PC whatever it's called unit.

In the end, I dont think you can go wrong, they're both good pieces of equipment that I think will provide you with the information necessary to implement a successful training program.