I have been following Cosmic since it's inception and Pop_Os! as well. For context, I was very against the Gnome 2 to Gnome 3 transition at the time because it destroyed so many useful and (at the time) did not replace them with an alternative. System76 is very hit-and-miss with their hardware (it's often pretty bad) but they are getting better at software over time.
As a Linux user or a developer, Cosmic is not something I can touch right now. I'm super excited for the future of it and they are making a lot of waves. They are giving Gnome the kick they need in making a functional desktop for real users. The fact that Gnome still comes out of the box with no real solution for multitasking (dock, bar, something) other than to randomly hit the super key or jam your mouse into a corner is insane. Every distro and 99% of users are installing some kind of multitasking aid (you don't count if you're using a tiling window manager)
I don't know all the specifics, but they also seem to be putting a realistic alternative to some of the plans, protocols, etc. Right now we have Gnome and KDE. KDE mostly does their own stuff and works with the FreeDesktop groups. Gnome works with them too, but more in a way of "here is what Gnome is doing you'll follow suite" kind of way. Having Cosmic as an option for people who want things closer to Gnome than KDE but don't want to deal with the "Gnome problems" will be good.