I have had many Maglites over the years, of almost every description. I have hurled a few of them into ravines and such in frustration. I have converted some to LED (although I have never owned a factory LED Maglite), and I have built several high-performance modified incandescent Maglites. The one I am writing about today I bought because it was on sale at a price I couldn't pass up, and I used it in its factory configuration because it included batteries and my frugal nature dictated that I use them before I starting hacking the light. Once those batteries were spent, I hadn't decided which modification to go with. But the light was pretty useful as-is, so I just stuck another pair of alkalines in it and continued to use it. Now, I have pretty much decided to keep it stock. This light is the basic 2-D-cell Maglite.
I have a couple of 2-C Maglites that blow it away. They are different versions of the MAG-ROP LE (Roar Of the Pelican, Lithium Edition). They are useful, but they are race horses. The stock 2D is a mule.
The 2D doesn't put out a whole lot of light. If I hear a noise outside and want to see if if feral dogs are after my livestock, for example, the 2D won't cut it. But if I'm working on the generator at night during a power outage, that 2D provides hours and hours of just enough light without flickering, overheating or fading. That has an appeal all its own.
Of course, most people use LED lights for that sort of thing (and everything else, pretty much) nowadays. But for most of my life the go-to flashlight for just about everyone was the plain old 2D incandescent that every flashlight company produced. It is one of those tools that gets forgotten because it just does its job with a minimum of fuss. Sure, it's "brown" light, compared to the blueish glow of an LED or the bright white of an overdriven halogen. But that reliable brown light has a certain nostalgic quality, for me at least. And incans are EMP-proof, for those who are worried about that.
Larger Maglites produce more light, and can even double as a defensive weapon. But they are physically harder on the batteries, too. In my experience the larger the Maglite, the more trouble you will have with it. There are more cell-to-cell connections, and they are prone to go black just as something moves in your peripheral vision at night. For me, a 3-cell is generally the maximum length for reliability in an unmodified Maglite. But the 2D version really shines (sorry) because it combines the reliability and long battery and bulb life of the ubiquitous 2D flashlight with the sturdy, water-resistant aluminum body of the Maglite. That makes it basic equipment at my homestead.