what's better for running 6s?

[tomstoys2]

Looking at buying some 3s packs to run 6s in a few of my boats. Most have stock BJ motors.
I'm looking at the Zippy Flightmax. My questions is what would be better:
5800mAh 3S1P 30C
5000mAh 3S1P 40C

Any benefits either way? The 5800 should have longer run times right? Would both give me the same top speed?

Thanks,
Tom

[LarrysDrifter]

I dont think you actually see any difference in speed.The extra 800mah wont be noticable either as far as run times go.Id get the 5000mah 40c.The higher c rating is always better.