I got a Damage Industries Enhanced Combat System mil-spec diameter buttstock, because it was marked down substantially. From $89.95 to $22.95 substantially. I got mine in foliage green, but the deal extends to all of their colors but black.
I'm going to keep using that word, substantial, to describe this thing.
It's substantial. It adds about an inch of pull at a given detent. It's heavy, 11.9 ounces. The Enhanced M4 stock shown with it is a mere 6.7 oz. (7 oz. with the optional sling loop). By way of comparison a Magpul CTR stock tares at 9.2 oz. and the SOPMOD stock it's clearly intended to compete with is 11 oz.
It's substantially wider because of the storage tubes.
The tube caps are o-ring sealed and well retained by a tab and a bit of a detent. The "pointer" actually ramps along the front edge of the stock, aiding in the removal of the cap!
I am not sure what substances I can stuff in them. Batteries come to mind. They're way too narrow a diameter to fit any of the oil bottles I have around here, and a boresnake just won't fit.
I'm a little concerned about that gaping maw there accumulating dirt and crud.
The paddle to change the length is also much wider than normal M4 stocks.
Shouldering is... different. Not bad. But not "WOW!" either. It just sort of is. Because it's so different from other stocks I've played with, I'm not getting a consistent cheek weld, but it's clearly unfamiliarity.
It's got almost no wobble. Unlike Magpul's CTR, which has a latch that presses against the spline of the receiver extension, the ECS stock has leaf springs that press against the tube at all times.
Plus! So far it's not grabbed my beard. That puts it at least half a step above most of the competition.