I have a friend who swears by lithium dispoables in his r09hr. Given the low-cost via mail order and the long life, the price-performance is Very good.
I have used NiMH's but they haven't been all that reliable as they age (and keeping track of newer vs. older ones is a drag).. I'm sure a better charger would help a lot. So for critical shows, I've been turning to alkies.