Chaser- I put a Mako buttstock on my Bushmaster Carbon 15 AR... $85 as opposed to $131 for the LUTH.
I like the height adjustable cheek riser:
Just be warned- if you order one from Mako, MAKE SURE that they actually have it in stock. It took me almost 3 months to get mine, with repetitive excuses as to expected delivery date.
I have to say, it was well worth the wait.