The 300BLK looks cool as hell. I'm just waiting for my barrel to get here and I'll have one.
That said, if you're going to get into the cartridge, plan on A) reloading for it; B) suppressing it; and C) short barreling it.
You can get factory ammo, but right now it's scarce and expensive. BUT it uses regular .308" bullets, which are plentiful, and you can convert .223/5.56 brass to .300BLK.
Since it's so easy to load subsonic, not suppressing it would be a waste of it's capabilities, imho. Same goes for 300 Whisper. Short barreling goes hand-in-hand with subsonic loading. Longer barrels will produce higher muzzle velocities. Loading it down enough to get subsonic out of a long barrel might not produce enough gas pressure to cycle the action.