What do you folks think of aluminum sided trailers?

^ This.
Think we're at 50-50 after 3 pages.....
It's a camper. Unless you're spending months a year in it and have no intention of covering or garaging it when not in use, your ROI on a more expensive trailer will likely be lost pretty quickly once it gets on in years.
Save for a few "highly regarded" brands that maintain significantly better value either through name, reputation, or construction methods.