i've been using tenegy for a while started w/ their blue 3800mah stick packs, beat the heck out of them. was real satisfied w/ performance
got their first 4500 singles (also blue) even tho i mistreated them, had them for a while & they still top out at 4200

just got the propels 4500 (12 pcs) haven't really had a chance to really run them, only ran once for each pack but i think tenegy is an up & coming company