I can only speak to the Stag AR15 models; and what I say is that I like them.
I own a air of the 24" 223 Bull Barrel Varminters, one of them for about a half dozen years. It's been very accurate and completely trouble free.
My second one was built using the builders' kit and a basic stripped Stag lower receiver. Performance-wise, if I hadn't put a Luth AR MBA-1 stock on one, I wouldn't be able to tell them apart except for the multi caliber marking on the stripped receiver.
I would recommend a builders' kit for your Stag-10, it's really a very easy assembly process, starting with a factory completed Upper and BCG. The Stag-10 system is essentially DPMS Pattern which uses different pins (I think better pins), but it makes using the Stag Upper and Lower together a necessity (with which I have no problem).
My only reason for not having one already is the lack of a .260 chambering in the product line. I also really want a fairly pain-vanilla AR-10 .308, and have been weighing the Stag 10 .308 versions for some time. Of course a Stag-10 .308 with a .260 swap barrel/upper is not such a terrible solution, either.
Greg