Basicly any PV that uses a straight Li-ion battery will perform for the same amount of time relatively speaking.... so the higher the mah the longer the charge will last.
Like Kent stated the eGo type e-cig battery sort of shoots the mah to the side... and you tend to get a longer lasting charge due to the circuitry of the device.
Regulated PV's i.e. 5v or variable voltage PV's will extend the last of the charge over the unregulated ones @ 6v... this is all to be compared with the same atty.. since resistance of the atty plays a big part on how long a charge lasts due to power usage (i.e. LR atties with low resistance puts out more current in turn using up the charge much faster)
now there is one battery that you can sort of throw the mah out the window,for the most part, and those are the LiMN high drain batteries. Now with in this battery type the "higher mah longer lasting charge" concept is still in affect, but (with out getting too technical) compared to Li-ion it is supposedly above par.. the reason being it has a different discharge curve.. (I am sorry I can't explain what I know

) so the battery's charge holds a bit longer.. and you get a consistent vape for a longer time.
Of course most of this really doesn't factor in with the PV itself... so the first part of my post is all that is really needed
LGD