which form factor of light do you hate?

[GoVegan]

No, I'm speaking specifically about Maglites with 3xAAA battery requirements, not junk flashlights. Aside from the terrible form factor, Maglites have notoriously poor regulators, bad selection of brightness modes, and poor UIs.

The fact that a 1xAA battery requires a voltage doubler does not in anyway imply that the tradeoff isn't a good design decision, given that it enables the use of a superior battery configuration. An Energizer L91 can provide over 3 times the capacity of an L92 at the same current drain, and has a maximum continuous current rating 66% percent greater, and a maximum pulse current rating 100% greater.

1xAA lights are easily capable of delivering 100+ lumens with reasonable battery life, and a 1xAA flashlight with a spare AA battery in my handbag still takes up less space together than any 3xAAA device.

And let's face it, for what most people need a flashlight for on a daily basis, 100+ lumens is really not needed. The vast majority of my flashlight use, my need is for sub-10 lumens, with the much less occasional need for 40-60 lumens, and only rarely would I ever actually need 100+ lumens. If I'm going to be in a situation where 100+ lumens is likely to be used, I'm going to use something with a much larger battery capacity than 3xAAA, anyway.

I'd much rather have a 2xAA Fenix E20, which is more or less the same size as a Maglite XL200, 0.2" longer, and 0.2" thinner.

Regarding the form factor of AAA vs AA lights.

For the last 10 years, I have carried a small AAA light (Fenix E01) on my keychain, normally as a backup to a larger 1xAA or a 1xCR123 light in my opposite pocket. Although sometimes especially in summer and in shorts or out running with a primary headlamp, then I've only carried the 1xAAA light (as on my keys). In all these occasions I would not have carried an AA light, as simply for me that form factor is too big and heavy to attach to my keyring.

For the people that I gifted the Fenix E01 to too, they are also still carrying their lights on their keychains for past 10 years. If I would have gifted an AA light then it would never have been carried past the second day.
And as Henry (HDS) says: " A flashlight is only useful if you have it with you when you need it.". I think we can all agree with that.
So for non-flashaholics, I think small lights like the Olight i3E are invaluable, as they get carried everywhere when attached to keys.

BTW I'd recommend carrying Eneloops in any EDC light, as they hold a charge for upto 10 and can be used down to -20c, so nearly as good as lithiums, but you also have the advantage of always being able to leave the house with a full capacity battery, otherwise at some point you'll be walking around with a Lithium with only 10% capacity remaining and won't even be aware of it.
Best of all, no waste for the environment, and a lot cheaper to run.

One other thing about the AAA form factor, over the years, I've often carried a small Streamlight Microstream in my work shirt pocket, again any AA light (for me) would be too big and/or heavy, as even the SL is pushing it sometimes when wearing a thing shirt.

AAA lights also make great wallet lights, kept in the center of the wallet or clipped to the side. Although I don't personally carry a light in my wallet, I can see the benefit for some.

 

[bykfixer]

Push button, out comes light……
Good enough for me. I grew up in the wack-a-palm days so if it works, I like it.

 

[snakebite]

with few exceptions coin/button cell lights.

 

[Labrador72]

I don't like the 2X18650 in parallel or multiple 18650. I never liked the 1xCR123 or 1x16340 lights either.

More to do with aesthetics than form factor, but I don't like lights without crenulations though I do avoid lights with aggressive crenulation.
I also tend to stir away from side swtiches.