I have a pair that have almost a year of riding on them, so about 3000 miles. I had to overhaul one of them a couple months back, though. On one hand, I didn't think that should be necessary so soon; on the other hand, at least it was possible to overhaul the pedal. Other than that, I don't like them very much, for a couple reasons:
--they unfold themselves at inopportune moments, like when I'm walking with the bike folded in a crowd getting on an escalator to the train platform.
--even when folded, they're pretty wide
--very slippery, especially when wet; hard to keep your feet on 'em, depending on your shoes, of course