I think the Penquins are more expensive because of the lower profile.
I got mine for under $600 and a free portable picnic table

from a deal Camping World was running.
The deal was they offered installation for $1. Once I told them it was for a '71 Airstream the got extermely busy to fit me in their schedule.
So I said wait a minute. That's the deal. Free installation! Or.... take the full installtation price off the price of the Penquin and I'll go away happy.
So they did it
I ordered the drain pan from an AS dealer and put it in myself.
That's the other thing you have to think about. They only make the drain pan for the Penquin. Otherwise you end up with condinsation water running down the side of your trailer
We were using ours on a 100 degree day and I saw a lot of water under the street side wheel. I at first though there was a plumbing leak until I realized it was the drain line from the A/C!
Good luck!