On Sunday's ride, a noob showed up with a brand-spankin'-new Schwinn Varsity, a flat bar road bike/hybrid, from Wal-Mart. Once he figured out how to ride (first time on a bike in 20 years and had just bought the bike that day), he did okay. Toward the end of the ride though, he was having shifting problems. Upon inspection of his rear derailleur, I found a Shimano-branded device with limit screws that were self-tapped into a plastic body. Functional? Yes. Durable? If set up properly and not abuse, maybe. But if you fiddle with it too much, or if someone puts the screw in crooked (which is what it looked like when I examined it), the RD is basically junk.

Yes I know there are people that get years out of their Wal-Mart bikes, but I think you're far more likely to have something break than on a bike bought at an LBS.