10440 will beat NiMH (Eneloop) at all brightness levels. L92 will probably be better but doubt it'll beat 10440 by much if at all... and then considering its $15 for a charger and two 10440s from AW, why not?
Just keep in mind at all settings 10440 is going to be twice as bright as NiMH/L92. So if you like NiMH at 100% you only need to set it to 50% with a 10440. THis is good all the way to the lowest light levels.
If you want an extremely dim light, NiMH at 0.2% is the best you can do. 10440 will be about twice as bright-- which can then be a downside.
Also with 10440 make sure you turn on the the battery protection thing... so it shuts off before you over discharge as there are no protected 10440s.