I’ve shot the 16” 223 once and SBR 300BLK a few times. Love the little thing, 16” appeals most to me and I want one but I don’t $3K want one. They were all very accurate. One of the times I shot the 300BLK SBR was at JTAC when kit badger did the coast to coast deal. After one sighter I was rocking the shit out of a 500 yard 1/3 IPSC with the cheap S&B FMJ they were supplying with a 1-6 Vudu on top. The gun was hot as fuck too, it wasn’t getting any breaks, one shooter after the other. That sold me on it. The other times I shot a 300BLK SBR was just a buddies close range with subs. The 223 I shot was with another buddies 77gr SMK loads shooting plates 400 to 600 yards and it was accurate AF.
If you like the fix you’ll like the mini. The only negative about it really is you’re stuck with AR mag length but with the performance of 77TMK’s it’s really not that big of an issue IMO.