73CJ see post #9
Considering the OP lives in AZ it is a fair assumption that rock crawling is pretty much what their wheeling terrain will be. I agree with 73CJ that for all other types of wheeling, trails, mud, sand, snow, etc. a fiberglass tub will work very well. My fiberglass tub is now 20 yrs old and still looks very good, but it has not seen much rock crawling in that time.
I have several friends who have aluminum bodies and just polished the tub instead of painting them and they look real nice.