Yes, Zamp is more expensive. Check this tour of the Zamp factory in Bend, Oregon
Scroll to about 6:15 to see the start of the Zamp tour. I expected Zamp just to purchase complete panels from China then just rivet on some hinges and legs and slap on a controller but they actually make panels from components.
Now that I have 200w of roof solar, soon to be 400w, I removed the Zamp controller and it plugs into the trailer solar system so I can plug the 200w portable in while the trailer is parked in partial or full shade. I have to carry the portables but since I have to carry two folding recliners the Zamp portable tucks in next the them so no big deal. You can see the Zamp case stuffed in with the recliners.