I use L2i 3xAAA with MF XM-L 3-mode and I really enjoy it.
Run time is shorter compared to 18650 and current draw is lower, but for my purposes it's fine, and I don't have to worry about heat (although at 2A the 3xAAA draw the flashlight heats up pretty well, with 3.2A the 18650 draws it would be too much). I need it for only a few minutes every day, so I have to charge it once a week.
And the L2i host is so cheap compared to what it gives you that I think getting another one is in place.
I have 2 L2i's and use 3xAAA in both. In one i have this drop in, which is a Solarforce 3 mode .8V-4.2V xp-g r5 and it works great, i usually keep 3 eneloops in it.
The other L2i has this drop in, which is a 1 mode 3V-18V xp-g r5.
both are very bright and i love being able to use AAA instead of 18650 in an emergency situation where i might not have access to 18650's