I used to have one, it was the quick release version. I didn't like that it was right next to the seat and had to move my saddle bag else where. Anything over 30lbs would put quite a bit of stress on it. If it wasn't clamped down super tight it would occasionally swing left or right. It was a lot cheaper than getting a rack that would accommodate fenders and disc brakes. I wouldn't say it was terrible, just not as good as a conventional one.