I use them occasionally. They arent the absolute best for burning compared to fresh lithiums, but they will keep a steady power going to it longer than alkalines or lithiums. When my lithium batteries stop giving green light from my laser, they still register as having little over half power left, which is bad since they cost a lot. Nimh batteries will keep giving about the same power until they are almost dead.
It really just comes down to if you want it really bright for a short period of time, or pretty bright for a longer period of time.