Yup, those are the same devices for roughly the same cost. Being the same devices, they fit the same niche regardless of vendor. I think Framework is selling this to step into the "home/smb ai enthusiast" market.

Id say their advantage over gmktech is the fact that you can buy just the mobo/cpu/ram combo. You dont have to buy the full desktop from framework, but you can. Thats "modular" in the scope of the platform. It lets you do wacky things like this video, where Jeff has already set up a half width rack mini cluster of 4 of them in an adhoc ai home lab data center experiment.