Honestly, after hearing a lot of reports about Knob Creek (including the ones bubbling over with praise), I really have little interest in going. I would rather go out with just one or two other people (just like a normal range trip). Then you can shoot at your own pace, not deal with crowds and noise, and enjoy the experience a lot more.
I'm lucky to have a number of friends with machine guns (and one of my own), so my point of view isn't the same as most folks'. Knob Creek sounds like no fun at all - mud and noise and such. Big Sandy costs $250/person to get into, plus paying for my own ammo and having to worry about strangers messing up my gun. Thanks, but no.
I have been to a couple much smaller private MG shoots, and those were a lot of fun. Everyone there was trustworthy and personally known, so it was a much calmer atmosphere. I got to shoot an M2 off a Humvee, an RPD, and a could other guns. I also got to share my NVGs and IR laser equipped AK with a bunch of enthusiastic newer shooters, which was a lot of fun.
Nowadays, I don't want to dump a belt through each gun on the line in order. I want to really get to know a gun, loading, unloading, disassembly, barrel changes, long bursts, short bursts, reactive steel targets, etc. Big MG shoots are not conducive to that type of experience, as far as I can see.