I bought one of these a couple of woots ago. I take my laptop to work every day, and then pack it up again to go home. Seems many things grow legs in the middle of the night at my workplace, so I wanted a cheap power supply that I could leave on my desk and not worry about if it too suddenly became "mobile". That way, I didn't have to wrap and stow the cord every day, plus getting to the wall plug requires a deep desk dive twice a day in this scenario.
This has worked great for me, for that purpose. No more desk diving, no more cord wrapping/stowing, and when it's time to go, I just unplug the laptop, and GO. Hey, Fred Flinstone has nothing on me when it's quitting time! (Yes, you probably have to be a dinosaur to get that reference!!)
Anyway, I don't have any problems with it turning off once I turn it on as some others have noted. I just manually turn it on in the morning, and that's it.
I'll be contemplating buying a backup all day today. So, if you're on the fence, better buy it now...or later might be too late..;)