NMiH batteries are smart although not as smart as Lithium Ion. This is to say that they will not develope "memory" like the prized NiCad of yesteryear. My expreience has been that they don't mind be "topped up" on a regular basis. In addition, the manual advises a 2-3 recharge time so they can certainly be fast and hard cycled.
A lot of the solution comes from greatly reduced internal battery impedance as compared to their alkaline and NiCad counterparts. The latter really just develope so much internal impedance that they won't provide the power to the load and also won't charge properly because of the internal impedance. Think of an additional unwanted load being placed between the battery and your Pronto leaving less than full voltage available at the Pronto. This is essentially what happens with older battery technologies.
The NMiH batteries offer a solution at reasonable cost that is quite reliable and long lasting.