I just bought 12 of the Eneloop 2500Mah black high capacity batteries for my 436HP so now its easier to keep them separate for the HP-1 and 436HP but I definitely like the longer running time on the 436HP as I get 8-9 hours on new batteries which may go a little longer after a few charges.
so far they are definitely worth the extra money for the running time. Great addition to the rest of the eneloops in my stable