Zamp is high quality stuff, but the price is way more than equivalent panels from Solar Blvd etc.
I have one Zamp panel, I got on a good deal when they first came out and there weren't many competitors. Since then added two Solar Blvd panels.
Does it work?? Well I have 240W of portable solar with MPPT controller as did the other party with us. and our last camping trip included 10 days of dry camping in National forest CG. With 100' of cable (#10) myself and the other couple were able to get the panels in the sun for 6-7 hrs/day. After 10 days, my battery bank was down to 90% SOC. Yup, only down 10%. His was down about 15%. That was after using the furnace for about 1hr/each morning, fans when needed, lights when we wanted to and reasonable but not anal power conservasoltion. Then we went to a dry camp with no trees, and 9 hours of sun and in 1 day both of us were up to 100% SOC.
Honda stayed in the truck bed. That said, when we dry camp and need/want AC, solar won't cut it.
For us, hardmount panels are limited value. 90% of the time we are parked under trees and limited/no solar. Portable lets us park where we want and still get solar. downside is you have to store them somewhere, they can develop "legs", and don't charge when your driving down the road.
Pick what works for you.