i'll just put in my 2 cents. my srm and pc7 cost less than a quarq. Now with my discount quarqs cost next to nothing, so it's a bit different, but for the regular person you can get an srm for less than a brand new quarq.
Their turn around time for me was phenomenal, but once again it all depends. I have not had a chance to deal with things breaking yet *knock on wood*, but i can't imagine that they are that bad.
I've had a quarq, a ptap and an srm. my srm is the most stable, followed by my quarq, and then the ptap was the worst by far (back to cycelops 5 times in 6 months).