I have been toying with the idea of selling off one of my uppers to pay for a BRN-180S, aesthetically I like ditching the receiver extension and having a folding stock.  Realistically that's the only reason I would be looking to make the switch.

Reading up on them however it seems they are anecdotally more reliable, cleaner, however run a bit hotter as the gas vents out the bottom.  Additionally I read that the barrel is pressed into a trunnion and not held in place with a traditional barrel nut.  This would make barrel changes essentially impossible for me.

Is there any other significant pros/cons to getting a BRN180 upper?

If you’re in CA and run a fixed mag/maglock set-up, then you can clear malfunctions and jams since you dont have the receiver extension to worry about.