That is in my humble opinion the biggest question! Of all three I didn’t even really consider the sheet metal and disregarded it quickly for the lack of experience and proper tools.
Wood is, what I feel most comfortable and enjoy working with. Unfortunately for me it takes a lot of planning and to make it look professional it needs a lot of iterations, plenty of cardboard templates and with just a little carelessness you have to start over. In addition to that it takes even more work to make the construction as lightweight as possible.
The finishing process of sanding, painting drying and more sanding etc. adds up in time and cost.
Upside is, I have all the necessary tools available.
Below you see my partially finished old setup based on a ground floor made out of two different types of wood (for weight savings) with integrated airline rails and finished with Raptor Liner paint.
Extruded Aluminum
You guessed it, I went for the well known Bosch Profile or 8020 to build my new 4×4 overland setup.
A frame construction for me has the benefit of being able to try out things on the go and reduce waste along the way. If something doesn’t fit, put it aside and use it later. Working with a frame also gives you the ability to replace fill in panels in case of damage or change them into hatches or drawers when ideas permit.
If it is really more lightweight is still to be determined. Since the amount of hardware that is needed to provide a strong frame is quite big. I go into more Detail about this here: Building with 8020 Extruded Aluminum
