the "best" pack for me is the Reedy Power 6000 Zapper SG2...
and not cause Im sponsored but because I run 98 to 99% consistency on a regular with them... they maintain great and always have power to spare. I don't "blast them" with my Icharger except to check IR and that's 30amps.... I use the Reedy Power charger 1216-C2, which charges at 12amps for my racing....