I've been using the OnGuards for two years without incident on my commuter/grocery-getter. I like them just for the convenience. When I go to the store, I just U-lock my top tube to something and I don't have to worry about the wheels or seat. I think a bike's most vulnerable area is the the handlebars. With the modern stems we have now, a thief could walk off with a nice set of shifters and handlebars in about 30 seconds using only a Park Cable cutter and an allen wrench. I use an old-school threaded headset and quill stem on my commuter for this reason.