What's fascinating is that 16:10 actually was vastly more popular as a
PC gaming aspect ratio just a few years ago. (
This Ars Technica forum comment describes those days pretty well, including Steam Hardware Survey results of the day.)
But over the past 2-4 years, PC gamers have increasingly accepted the console-standard 16:9 aspect ratio for gaming. I make no value judgment about that; just pointing it out.
As to whether 16:10 is "better" than 16:9... as Josh noted, it gets a little complicated.
The claim is frequently made that 16:9 is "wider" than 16:10 -- that is, you can see a little more of the game on the left and right sides in 16:9 than you can when playing in 16:10 mode. But that's an oversimplification.
There are a couple of things actually happening here. One is that 16:9 is
only wider if you change the Field of View (FOV). This is because the number of pixels is different. For example, 1920x1080 (16:9) displays fewer pixels than 1920x1200 (16:10). 1920x1200 = 2,304,000 pixels, while 1920x1080 = 2,073,600 pixels -- a 10% reduction.
So to keep the horizontal elements of a game from scaling differently (being wider or narrower than intended), the FOV has to be changed (as Josh pointed out). Thus, saying that "16:9 is wider" is true only if you increase the FOV to preserve the same perspective as 16:10... and not everybody likes a wider FOV. (Wide FOV is a primary cause of motion sickness in some gamers.)
So what happens if you maintain the FOV? When that's held constant, here's the real difference between 16:10 and 16:9:
This would be the primary support for a claim that 16:10 is "better." At the same FOV, you see more pixels in 16:10 than 16:9.
And that leads to the other point: if you make a game meant for 16:9 monitors, how do you choose to display it on 16:10 monitors, and vice versa? This is mostly a question for developers of console games with fixed 16:9 aspect ratios, since PC games have historically had good support for numerous screen resolutions.
When trying to support different monitor aspect ratios, console game devs will use what the Widescreen Gaming Forum called "Vert-" and "Hor+" modes. These are two different ways in which developers try to insure that 16:9 and 16:10 monitors both show exactly the same amount of gameworld. Hor+ means that the game actually knows to display more of the gameworld by extending the left and right areas and changing the FOV.
Vert-, on the other hand, is what developers of console games do when they feel they have to maintain a desired FOV when their game is ported to PC: they just don't display the top and bottom slivers of the gameworld, essentially letterboxing the game. It's basically taking the top and bottom sections from the image shown above and blanking them out, eliminating the pixel count advantage of a monitor designed for 16:10 output.
All this is an explanation. It doesn't really address the reality that PC gamers today, for whatever reason, have largely accepted the 16:9 aspect ratio of console games and the FOV that comes with it.
Which I guess is one more reason to be glad there are still PC-original games being made, such as Limit Theory, that are designed to be aspect ratio-agnostic.
I bet LT is going to be jaw-droppingly gorgeous on a 21:9 ultra-wide monitor.