Stag 10 without question.
Stag's parent company was CMT which is a huge manufacturer of OEM AR parts. They didn't reinvent the wheel or have to go to sub par parts when creating their rifles.
From Arms East's website:
Why choose Stag Arms for your AR15?
Stag Arms and Continental Machine Tool represent over 30 years of M16 and AR-15 OEM manufacturing experience.
Stag Arms manufactures 100% of its major components in their modern New Britain, CT, USA factory.
As the manufacturer, Stag offers Total Quality Control over all stages of manufacture and assembly.
The BCG on the Stag 10 is nirited and MPI. The MH is DPMS oem lowest bid gen1 with an American Spirit Arms inspired notch cut into it for the side charging handle.
The biggest factors for accuracy with the Stag 10 will be the barrel, trigger and ammunition. Setup for accuracy your Stag 10 should be aiming for .5 moa, 5 rounds at 100 yards capable. The MH isn't and 1 moa is what people are chasing. It's unknown why. But the MH accuracy really doesn't live up to the AR10/AR308 accuracy potential. Piston system AR308 rifles are shooting better than the MH. Some owners have gone to a barrel change for the MH and while those that did so have reported good reliability along with 1 moa performance. 1 moa isn't the dragon you should be chasing with an AR10/AR308. .5 moa is where you want to be aiming for.
Further with accuracy expectations/potential. The Stag 6R 223 rifle I bought came with a .5 moa guarantee. The only other precision AR15 at the time with that same guarantee was the Les Bauer. The only thing they did to the 6 was the barrel and trigger. Everything else was standard Stag AR15.
I would put the Stag 10 on Par with the Armalite AR10. It's better for modding or building though due to it's DPMS style parts compatibility which is the most common standard for the AR308 rifle and offers the most aftermarket options. These are good quality work horse AR rifles that are well done but don't offer all the boutique features of high end AR rifles such as the KAC/LMT and HK etc (yes there are many others as well). I mention this because the AR10 has seen combat, is reliable, built well and with the right parts is exceptionally accurate. Not as fancy as LMT etc but it gets the job done and does it very well. It's not hobby grade. The two other non restricted options are hobby grade.
The Modern Hunter isn't even a distant third choice with the Stag 10 being introduced. The Stag has the MH beat on build quality, I mean real build quality not expensive window dressing. It beats the MH on accuracy potential, reliability, magazine compatibility, ammunition that it will shoot, parts compatibility and trigger options. It's also available from the factory in 6.5 CM. Now add in that it's approximately $1300 less for a complete rifle. That's comparing a base model MH with DPMS furniture to a Stag 10 with better furniture and handguard. Is an ambi bolt release and side charging handle worth $1300? Also keeping in mind that modern AR charging handles offer side charger performance/function while also providing the ability for true ambi function. You can't switch over the side charger on the MH.
The MH was killed by the BCL 102. Both the MH and the BCL 102 just got blown out of the water with the Stag 10.