http://www.quarq.com/pages/upgrade-program
Just found out about this. I have the older quarq from 4 years ago (SRAM S975 power meter owners) so looks tempting. I was thinking of upgrading to the SRAM Red 22. A few questions:
I disn’t buy one, but quarq warrantied my 975 for a riken. I don’t believe there are any differences in ride( very slightly heavier), but the main difference is one of user friendliness and reliability. The local dealer admits the s975 had loads of problems which have been improved upon in the newer series. the led and New battery size make things more user friendly as well
I used my Cinqo for a couple years. Upgraded to a Riken 10R.
The LED that blinks when the PM turns on is nice to see that it’s actually awake. Other than that, I’m failing to see much of a difference.
Well, warranty is now good for another 2 years so I got that going for me 
Accuracy is slightly better (1.5%).
ELSA does quadrant analysis and provides data on L/R balance (Riken doesn’t though).
You have the opportunity to get a different chain ring size or crank length set-up versus what you are currently using.
Refreshed warranty.
Same here. I heard that the cadence switch inside is suspect after a lot of use and this is probably why they are offering the deal - better to swap out the suspect units and get some payback rather than get them back next year and have to warranty them.
The Riken is just as good as the 975 but I like the LED light a lot.