My experience is with the Stag Model 6 Super Varminter, which has been superceded this Summer by the
Stag 15 Varminter (
$1084.99 on sale for $815), and is excellent. Except for the substitution with the Magpul stock, the 15 Varminter is the identical rifle. I've had the 6 for going on 8 years, and for a factory varmint rifle, it's very accurate ad very reliable. I saw one in the LGS, handled it, and immediately ordered one after seeing several targets fired at 100yd with PPU 69gr Target. Love it and use the lower as a foundation for 3 other Uppers. It is a very good rifle with 75gr bullets, and has been shot in National MR 600 F T/R comp.
Following that comp, I gave mine to our Granddaughter, and bought the kit version as a replacement. It came with the same 24" 1:8" Stainless (very possibly a McGowan) bull barreled upper completely assembled, and everything for the lower (including a decent 2-stage drop-in trigger assembly) without the stripped receiver. My first ever lower build, it went together in under a half hour and no issues then or at the range.
The
kit is roughly $810, and the
stripped lower is around $85. The primary advantage to going this way is that you get a fully compatible and tested setup at builder pricing. It will work as advertised and have manufacturer support.
When I built mine, all I replaced was a substitution with a Luth AR MBA-1 fully adjustable stock, and I added a BAD Lever. In all ways, it serves well, and is also a good lower to put other uppers onto. No issues with any other Upper (CMMG 16 Bull Wasp, AR Stoner lightweight 16", and a Franken-Upper based around a Stag 3G 16" Barrel) so far.
I think it's a great rifle at a good price, and is not full of the uncertainties and teething issues one could encounter when doing a Franken-AR.
Greg