Not talking about it being my primary weapon. Simply a side arm to take along. But this was asking about the gun and if anyone has used one and how it helps with mounted shooting and possibly as a utility type gun.
The concept behind the short barrel is that it is quicker to draw and holster than a longer barrel. At the higher levels of competition, matches are often decided by fractions of a second. Everyone is looking for every advantage they can get.
The shorter barrel also reduces weight (less metal). It also changes the balance of the gun in your hand. For speed events such as CMS, both can be an advantage for the shooter.
The Ubertis are imported by a few companies. I am guessing that you may have seen the "Taylor's Runnin' Iron" which is a short barrel that gets a bit of publicity. I have heard many good things about the Runnin' Iron, although I have never used one. Taylor, as a rule, produces very good products.
The other popular short barrel .45 is the Ruger Montado (which is not an Uberti). This can be very hard to find in stock.
I have a pair of Montados (actually they are my wife's). Like other Ruger products they have a very good build quality and have been very reliable.
Both Montado and Runnin' Irons also have turned down hammers, making them easier to cock. This is very helpful for mounted shooting.
I can't speak to the utility of either as an everyday carry gun. Honestly, that isn't what they were designed for, so I am sure there are better options.