Smack whoever is marketing it as a 5C cell in the balls. It will perform like absolute crap, waste tons of energy, and generate loads of heat even below that rating. Other resellers call it a 3C battery, but it isn't even that; that's more like a burst rating for a short period of time.
On a 2C constant load, it looks like she's a ~3.4v nominal cell instead of the best case scenario: about 3.7v nominal. It will blow ~10% of it's energy as heat. That's far from optimal.
You'll notice that the only way to get full capacity here is to run it at 0.1C. But that's not the kicker... the voltage you lose is what hurts.
This is the ugly truth about high capacity 18650's over say, 2500AH or so.. they have great energy capacity, but awful power. You either have to oversize your pack significantly or run low power.
You will notice with cell_man's batteries, that the mentions a more realistic power level of the his cells instead of parroting whatever the manufacturer's 'burst'/max C rating is, as if it was some kind of constant rating! A lot of resellers do that - and that's either dishonesty or just plain not testing their product and selling it correctly.
