I've got two BHW mid-length barrels. A 16", .750 gas block, 1:8 Standard profile 5.56x45 and a 18" 6x45 (.750 gas block, 1:10 standard profile). Both are very soft shooting compared to a S&W M&P 15 16" carbine that I have. Add a heavy buffer to it and the recoil will be like shooting a .22lr rifle. You can see my 16" middy 5.56 here www.blackholeweaponry.proboards.com/index.cgi?board=photos&action=display&thread=754.
The one disadvantage is that you will probably need to get a longer free-float tube to cover the gas block (if that's important to you). I went with an 11" hand guard to cover the gas block and also give me a longer sight radius when using the BUIS. Apart from that, the middy 16" runs great.
A good combo, IMO. I went with the mid-length system because I feel cramped with the shorter carbine handguards. My BHW barrel is quite accurate & seems to handle various ammo reliably. Ya can't ask for more than that.