I don't currently have one, but I will be getting one soon. Years ago I was big into revolvers and believed a big bore .44 or .45 were the best choice for power and they are powerful, but they're not practical for any sort of carrying role because they are so big and heavy.
The 10mm is 15+1 of hand cannon hellfire and IMO a true combat pistol caliber. The .45 has its place, great for suppressors and special ops, good for home defense with the lower hard barrier penetration, but as an all around variety caliber it's not better than 10mm in performance; it is in ammo price and I think that's largely the reason why people don't gravitate to 10mm more.
Fact is the factory ammo 10mm is expensive and unnecessarily so because it's basically .40 S&W with a longer case and a few pennies more in powder. A $1 more per box for 180 grain FMJ I can understand, more brass and powder being used, but $10 more a box... please.
I had no interest in 10mm until I started reloading, then I realized I could make my own full power 10 ammo. Well, close to full power, something above the usual 1050 fps with a 180 grain bullet. IMO, if you don't currently reload and don't plan on buying any revolvers, reloading for 10mm is the answer and worth doing. It's not necessary given if you buy a 10mm Glock you can shoot .40 S&W in it, but if you want more power, unless you got money, you have to load it if you want to shoot 10mm.
That's another thing I like with 10: you can shoot .40 in it with a Glock. If I had known that in 2016, I wouldn't have bought a new Glock 35. I did buy a 9mm barrel for that G35 tho, so it's not a total waste, nor was the used G27 at used .40 prices and I'd rather have the 27 than a 29, I don't see the benefit to 10mm in a short barrel with a short grip. That's more recoil and blast with less velocity all for concealability.
The 10mm wasn't built for concealment, 9mm and .40 are.
People will say .45 has less recoil and blast than 10mm, but if you were to compare a low power 10mm load, something close to .40 S&W power, there'd be no difference and it's that variety of power with 10mm you can get that I like. You want an improved power .40 S&W JHP ammo? You can get that with 10mm. You want to load for bear? You can get that with 10mm.
The biggest benefit with 10mm is it makes the .357 revolver and even the .44 Special and Magnums obsolete. Yeah, the .357 and .44 Spc are great for self defense, .44 Mag for big animals in the woods, but unless you're carrying some Scandium frame S&W or a Charter Bulldog, those revolvers weigh you down and give you 10 less rounds to work with.
A lot is being made about 9mm and LE organizations moving back to it and the talking point being improvements to bullets make it more effective now, but the reason it was done is largely price and lower recoil. If LE could get .40/.45/10mm as cheap as 9mm, they would choose that.