About a year ago, I reluctantly put on a pair of Planet Bike Freddy Fenders Speedez (the quick-attach model with rubber attachments) on my commuter because the frame wouldn't fit screw-in fender models.
I was reluctant because I thought the elements would wear down the rubber and they would fall off or at the least, become loose and rattle.
I'm happy to report that after one year and about 8000 miles through a harsh Colorado winter and spring, they've yet to deteroriate at all. They're still attached well and taking a beating. So, anyone thinking of giving these a go, I'd say, for $35, you'll get a minimum of a year out of them (a bargain) and likely longer. A good purchase.

I have been using them for 4.5 yrs now and they've been ok. The rubber bands that hold them to the frame/fork died long ago but zip ties seem to be holding up. I would prefer a proper frame w/proper fenders but in a pinch (a 4.5 year pinch yes) they are adequate.