I recommend you use a 16V version. 10V is fine but as mentioned it is always better to have extra headroom so not to stress the CAP, especially in high temperatures.
See if there is a temperature rating written onthe cap. I suggest to use a rating of 105 (degrees celcius, not F!) The reason is also for reliability.
Now the difficult bit is the ESR, the lower in theory is better. This relates to the quality of the Capacitor.
As to its value, I have seen people using fronm 1500 to 22000uF. What is the difference? Well, this is the sort of a black-art part. But lets see if we can decide this after knowing what is the CAP there for:
NICADS and NIMH generally has a high internal resistance, that means it is slow to react to small spikes ir instant current draws(whether from interference from high current fluctuations). Also one can consider that it will have a limited instantaneous current flow limited by its internal resistance.
I read many ESC instructions saying it needs a cap for the ESC to run better, this is normally because the new generation of ESC can only be so small without the cap in question. So they take it outside! Now no one is complaining about the size of their ESC! I mean this is really silly but it is obviously working for them. Who want s a brick sized ESC anymore??? Just think about it.... they used to have them inside, but not anymore??? why is that then??? I tellya, they can shrink IC's and transistors, but when it comes to storage caps, the size is always an issue..... it happens in all fields of electronics....
So what do we get out of it...?? Well, thing is, by using a different type of CAP does have different effects on the outcome in performance.... A large cap with a low ESR can actually supply a much higher instant peak current than any type of battery used in RC. But a large CAP is not so good at filtering small spikes of interference and it takes longer to replenish it self..... So some people noticed more punch with a large'ish cap, but they do try a few within a range and can notice there is a sweet spot value they prefer (and bigger is NOT always better!), this can be related to the operating frequency of the ESC and basically there can be a cap value that works best with the ESC freq. The sweet spot I supposed it is where it works best under the given operating conditions i.e. the cap can charge and discharge most effectively within the operating frequency of the ESC.
As for supression, the rule of thumb is if you want to eliminate as much intereference as poss, the supression device (CAP/Shottky) it has to be as near to the device you want to supress, like soldering the diode and cap on the motor is always better than somewhere down the line where the interference can radiate from the wires. The CAP should be as close to the ESC as possible so that the little distance of wire from the CAP and the ESC have little chance of picking up intereference. Naturally I hope there is a small cap inside the ESC to take care of small spikes which the large cap are unable to filter....
Anyway, that's my 1 penny worth!