I have had one of these chargers for 3 years and have had no problems with it.
Can't add much to Brad's post but one other problem I have heard of is trying to charge a battery that has been over discharged, If a cell has been damaged it can confuse the charger and it picks the wrong cell count. Usually it will count low which will only terminate the charge early but if the cell has shorted it can cause high voltage and the cell count will be high, causing a exploded lipo if not caught soon.
I have been using lipo's for 3+ years in my airplanes and have had many packs fail but never because of the charger. They have always been damaged by discharging at too high a current (All battery makers lie about their C ratings), discharging to lower than 3 volts per cell or by physical damage.
For the best advice I will quote BB
5. Keep an eye on the battery
Lockhart