I'd say most of the problems people have had with them have had more to do with the habits of the user, rather than the actual product itself. People are used to leaving their phones, laptops and tablets plugged in for a while, (sometimes overnight even!) this is not good for these things.
Follow these general rules with anything that uses a high performance lithium based battery, and your issues should be minimal;
1) NEVER leave the charging unit plugged in for longer than it needs to charge up the battery.
2) ALWAYS let the battery cool down from use before plugging it in to charge.
3) NEVER leave it plugged in overnight. If you aren't there to monitor it's state, don't plug it in.
4) NEVER run the thing until it stops. Always stop using the battery before the automatic cut-off kicks in. You're gonna have to determine what YOUR runtimes are. The ones in the manual are always going to be generalized and have nothing to do with how YOU use it.
5) IF you have a voltmeter, use it to check the state of the battery before you charge it, and after you're done using it. If you don't own a voltmeter, get one and learn to use it! It is a small investment that can save you lots of cash when it comes to batteries and other household things.
6) NEVER take advice for modifications or hacking the thing from youtube videos. The guy or gal on youtube does not pay your insurance, do they?
I sell these things and haven't had a single problem when I read our customers the riot act before they buy it.
Merry ChrismaHanukwanzikayule Everyone! (I know it's early, but it's the best time of year, and it should last well beyond when it's fashionable!)