Dooz, the J & S is not just more heavy duty but much more stable, I've had the Sears, Harbor Freight and 1 other and ended up giving them all away, if you are lifting your bike to clean it or do simple things they are ok, but with the cheaper jacks every time I'd remove my front tire I'd have to brace the rear end to keep it from tipping, I've done major work on the bike with the J&S , had the bike on it for months rolled it around all over the garage while doing it without and issue, you have to use one to understand the difference