LE and military services have to balance a lot of different things that aren't necessarily an issue for private citizens. They need a pistol that can be used by a wide range of people from a large enough manufacturer that can supply millions of units. They have specific performance requirements including environments that you probably will never find yourself in. They have budget parameters that are very different from an individual, as well as negotiating powers that no individual has. The local cops didn't choose their Glock 21, infantrymen didn't choose the P320, the decision was made for them.
My suggestion is to go to a large gun store with a range and rental pistols and try before you buy. The Arex looks like a ton of fun, but does it fit you well? Does your grip interfere with the slide stop or magazine release? How much are the magazines? Is there any aftermarket support for holsters and any other accessories you might want in the future?