036NHR v2 is claimed 2000mw output.
036NHV is claimed 1500mw output.
Owning both, I can tell you that the 036NHV is the better adapter all round. And it's less prone to burnout/breakage.
It's a newer chipset, yet the sensitivity figures for both adapters are roughly equal.
The modern drivers for the 036NHR v2 don't work too well with it, so you are stuck
with drivers from 2011 (Which excludes > Win 7 use properly as the TX output and SS and LQ bars are all messed up for the NHR v2)
Neither one of these stronger TX adapters will run on a lengthy 15m active USB extension without some kind of powered hub plugged in at the end, whereas the 036NHA, 036NH and 036H will without needing an additional power feed.
However both are really only of use in Windows as Linux support is spotty at best.
Also for the 036NHV I wouldn't recommend using any drivers higher than 1027.2...
...they be broke, signal strength readings messed up (and full signal and full link quality fake indicated always 100% on 1030.xx drivers +).