As far as problems, I haven't had any with mine after about 25 charges.
My complaint is that I can't charge over 4.5 amps and the voltage drop setting isn't very fine tunable. 5, 10, 20, 30, or 40 mv. I can't go over 40 mv like some hot packs call for. I guess I shouldn't be charging top end packs on that charger, though.
The buttons are stubborn and the wires are cheap, but in a way you do get what you pay for.
As far as the fan problem, I sit the charger on top of a fan out of an old ceramic heater that I use to cool my slot cars. It keeps the charger very cool so I can charge many packs at a time. I may install the PC fan, it would be a lot more convenient than that small heater fan.
Overall if I could go back and do it over, I wouldn't get it. I should have spent more on a better charger.