I LOVE my Debbie Meyer bags!!!! I have the green ones for produce as well as the bread bags. Yes, they really work; before I would always end up having to throw out lettuce, cucumbers, green onions etc. that would go bad before I had a chance to eat them (my kids are not big veggie eaters). Not anymore; my veggies stay freshin the bags for a minimum of two weeks. Same thing with bread; it keeps buns and such fresh for weeks. I rinse them out when they're empty, and dry them inside out on my drain board. Definitely worth the $20 investment for the two different kinds of bags, IMO. I bought mine about 18 months ago, and they're all in great shape.
This is kind of funny; I want to make banana bread today, so a few days ago I took three bananas out of a Debbie Meyer bag to make sure they would be ripe enough.