BRN-180 Gen 3 vs BRN-4

Hey guys. I been looking at these two guns, I wanna get either a long or short stroke piston gun going, and thought I'd ask on here if anyone has both, and if so, which one do you like better and why?

It sounds like the BRN-4 runs a bit slower, and rougher, and its quite a bit heavier. The folding stock for the BRN-180 looks good if it goes for 300 Blackout, and the handguard not being swappable on the BRN-180 kind of sucks with the thin barrel heating up so fast.

Help me brothers!