I started using regular eneloops in my first gen 2 cell and at first kept thinking I had forgotten to put batteries in it. I have one with 5000 mAh Imedion batteries in it and it's like picking up a lead weight in comparison. I set it side by side another 2 cell with a pair of eneloops for 2 years and the Imedion powered one was dead when I went to use it while the eneloop'd one fired right up. So if you use Imedions but store the light in a glove box etc keep tabs on how much self discharge has occured.
I was hoping to see an updated version of the 3 cell but so far no go. It's really a nice light. If the ML50 isn't too big to carry the 3 cell ML25 is a treat with it's ML25 beam in a classic 2C length package.
That's why I run mostly 18650's and 21700's in the 2 and 3 cell Mags, much lighter weight, often longer run times (particularly with 21700's) and you only have one cell to charge. The Soshine NiMH C's are pretty good, but they won't hold a charge like Eneloops.
A updated 3 cell ML25 would be great, I suppose Mag will do it at some point but it might take awhile, same thing with a dual mode 3D LED Maglite.
The ML25's are unbelievably size efficient compared to the old incan C cell Mags, the ML50's are not bad either, but there's no beating the ML25's.