It depends on what else you're going to do with the trailer. Do you need to haul stuff that can be loaded or unloaded with forks? Then a dump isn't for you. Do you need to haul dirt, stone, debris? Then you need a dump.
If you're going to have one trailer, you're going to have to compromise somewhere. Will you be using the trailer primarily for hauling your tractor, or material?
While tying a tractor down in a dump trailer is a little more difficult (allot more if you add side boards), there's an added measure of security in having the box to keep the tractor on the trailer.
The floor of my dump trailer is lower than the deck of my deck over flatbed.
I don't have any info about the brands of dumpers the OP mentioned. I looked at several brands before I decided to go with B&B (Behnke). It's 14' X 80" X 2' sides. 14K GVWR. It's hands down the best brand of dump trailer I looked at. Everything about it was built stronger or was thought out better than the other brands available around here. It has a single hyd cylinder with a scissor set up as opposed to twin cylinders that the cheaper trailers have. The single cyl set up is safer. That's why most HD dump trucks use them. The down side to B&B is the price. A 14'/14K GVWR dump will set you back over $7K compared to other brands in the $5K range.
Chris, That's a good looking trailer for hauling a tractor, lumber, firewood, etc. Doesn't look like it would be very useful for dirt, gravel, or debris because of the low sides and low dump angle. Still, it would be a good compromise for allot of folks.