I've been having the same debate with myself. The dump trailer is nice for hauling brush and logs and stumps. Yours is even longer than mine and I can see a lot of advantages when you are working on clearing one of those hurricane ravaged lots but you are right, a trailer is harder to move around and it is long and heavy behind a truck.
If you could swing both, having the dump trailer for the debris and the truck for materials would make sense.
"Life is tough, but it's tougher if you're stupid."