My mom and I stopped at El Cosmico on our road trip across the US last summer. When I booked it, I was under the impression from the photos that it was tucked a little ways away from the main road and we would feel somewhat secluded. Our teepee was nicely appointed and the bed was very comfortable. We did not get to get into the "communal" feel of the place too much because we were there during a stormy day, but the grounds seemed like they motivated some nice community. The place looks fantastic and the layout gives you some privacy while still allowing for mingling with other campers/guests if you'd like.
My only real complaint was the fact that the property is sandwiched between a pretty busy road and train tracks that have late night trains going through town. It was very noisy for a desert night. I really wasn't expecting that at all.
It's really easy to get into town (El Cosmico is barely outside of it) and it was simple to get to the viewing area for the Marfa lights (a must see!).