Don't know , depends if your bashing or racing . I am racing so i tried to keep the weight under 600g for the batteries since i use them in both the truggy and buggy , that's why i went with the 4350mah which is around 560g and balances well in the vehicles with enough runtime for me.

By the way the Zippy even though being 4000mah pack is getting around 4300mah back in when charging , and around 18 mins runtime , at $98 it can't be beat .It's just weighs over 600g so i will use it for heats and the PQ for finals.

The 5000mah pack might be ok in a truggy since the truggy is a lot heavier anyway but i don't think i would use it in a buggy .

Hopefully someone running one can chime in with there thoughts on this .