Picked up a couple packs of these last night. I can see a brightness and definitely a whiteness boost. I loaded up some nizn AA cells to see if I'd get overdrive or poof. My results using fully charged cells (but not fresh off the charger):
Nimh AAs: 370ma
Nizn AAs: 430ma
the bulb is ok so far. I used it for around 20 mins or more last night, and turned it on an off many times repeatedly. So far, so good. The extra voltage of the nizn cells is providing a nice little overdrive.
Having said that, I think it's important for us to remember that this isn't a hotwire. On nimh, its: 2.4V x .37A = .9W vs. 3.2V x .43A = 1.4W on nizn. So, the incan MM has improved, and to me, is now useable. I actually like it; something very old is new again!
Also, the mission of this light isn't a thrower or total output vehicle. Its a small, 2AA incan with a total lumen output of... 15-20 lumens or so. Nice. Because of this, I am using mine with a UCL-LCF lens to make the beam perfect smooth and floodier with no artifacts. Now, it fits into a niche in my incan arsenal of short range flooder at low power but with respectable whiteness.