I've used them for the past three years. I've had great success growing vegetables. The only complaint I have is the standing water in the reservoir. I've put vegetable oil in there for prevention of mosquitoes laying eggs but for some reason it didn't work and plus I think algae grew inside as well so the water had a funky odor.

This year I'm giving up using them and using grow bags instead to avoid the standing water issue. Also the fertilizer they sell, I'm not exactly sure what's in it so I only used it the first year.