Hola,
I have one AR pistol. It is a PSA PX-9 in 9mm. I purchased the the completed upper and lower separately. I added sights, optics, a brace and single poin sling (still looking for a light). It uses Glock mags. I am using a Kak brace, MBUIS and a red dot sight with a magnifier. It has the 10.5" barrel with M-lok handguard and a A2 style flash hider. My view on this?

I'm a Glock guy so having an AR style weapon system that: allows for interchangeable mags (it will even accept G26 mags); increases the effectiveness of the 9mm round; has common AR controls (and attachments), as well as giving me a shoulder able brace. I wish I would have done this in lieu of a Sub-2000 (nothing against the S2K, it just didn't work for me).