We did a 30x40 post frame with a 10' covered concrete on one side as well. Gober Post Frame did the work. No complaints, everything went smoothly. That was in 2015, I've heard good and bad reviews, both before we built and since, just like anything else. I did one large overhead and one walk thru at the opposite end for air flow. Assuming yours isn't going to be cooled, keep the orientation of the shop on site and location of the doors for the best air flow in the summer if possible. I figured I'd still need to have a large fan but so far it's been doable without one, we usually have no shortage of wind. We probably would have had room to do a 30x50 or a 40x40, but I'm not feeling crowded whatsoever with what we've got.
