I suppose the simple answer is: all else being equal (tone woods, scale length, frets clear of the body, string gauge...), the Jumbo will have more low-end rumble than the Dread, and may be a bit louder (more projection).
The Jumbo will also have a pinched waist compared to a Dread. Usually, they both have the same body-depth, but the Jumbo has a wider, "rounder" lower bout.
And, from your description, your looking at the MasterBilt series. Personally, I really like the off-set notch headstock on those.
Good luck in your decision!