Ti-Brook vs. Travis end dump

We are looking at buying an end dump for our farm. We are going to try to look at a couple tomorrow. One is a 1991 32' Ti-Brook electric tarp, alum wheels, spring ride; and the other is a 1992 35' Travis end dump. It has new brakes, drums, brake chambers, and 90% tires. Is there a huge difference between the two models? They are both a little shorter than I'd like, would like a 39 or 40'. Is it going to be too hard to get your weight on a shorter trailer if we end up hauling for someone else? And are there any major quality differences between the two that we need to be aware of? And if the trailers are basically equal, is air ride suspension worth $5000? I have pulled air ride and spring trailers in a chain floor but never in an end dump. Thanks