So I just finished putting together my new AR pistol and built it using the Thordsen Customs cheek rest and buffer tube kit. I'm pretty happy with it overall however it doesn't quite go the "extra mile" and I really think Magpul could probably produce a better product. Specific things which I think they could improve would be the inclusion of limited rotation QD sling cups along with improving the actual location of the cups so they aren't quite as in the way as on the Thordsen device. Additionally the Thordsen kit uses the CAA side saddle along with proprietary adapter shims to get it to fit onto their buffer tube cover; these could all be done away with if they were molded from a single piece. Additionally while the CAA part is serviceable I've never felt their quality was really up to par; their polymer feels quite flimsy especially when compared to Magpul's.
Magpul, if you're reading this, I know you have a lot of irons in the fire and the whole pistol category of ARs brings with a certain legal uncertainty (e.g. Sig Brace fiasco, anyone?) but I can't help but think the ATF would still classify any cheek rest you produce as just that (and not a stock). As such it would be nice to have some higher quality options available. On my particular pistol all the furniture is Magpul as are most of the accessories except for - of course - the buffer tube cover and cheek rest.
Just food for thought!