I've had my quadra's for about 2 months now and wear them everday. Whilst they are comfortable They are not the best trainers I've bought - but for £20 they are a bargain.
Just a few gripes though -
*They get very hot, not allowing your feet to breath is a big downer for me, but once again - you get what you pay for.
*They are not water resistant - or at least not enough for me (saying that I work in an aquarium).
*The tread has nearly worn through - I walk to and from work everyday as well as spending all day in them, so they do approximately 4 miles a day. I reckon maybe another months work and they'll get binned.
All in all not a bad purchase, worth the money but not in it for the long haul. I'm certainly going to save up next time and get myself some salomon's.