The main complaint I've seen on this charger is the voltage measurement accuracy is poor impacting the balancing of lipos as well. There's an extensive thread on RC Groups on how to fix it - requires replacing some resistors internally with better quality ones, but why bother, just buy a better charger.
http://www.rcgroups.com/forums/showt...light=imaxx+b6
I guess you can try it a see how it does, the quest was asked late in the thread if the current produced ones still had the prob, but I didn't see anyone answer it. If you have an accurate DVM you can trust, you might want to check the voltage you're getting from the charger.