There are plenty fo subgroups in each of those camps; however, keep in mind that what I am about to write applies to all of them regardless of how they differentiate amongst themselves.
Everyone generally knows what a Futurist or Dispensationalist believes — Christ is still to return, bible prophecies remain unfulfilled, and the like. A Preterist believes, for the most part, that all of the biblical prophecies have been fulfilled. As previously discussed, prophecy is not about the future, about about revealing the ongoing move of God in the world around us. A prophet, then, did not issue foretellings about some long distant event, but told what was happening or what was about to happen. Seeing as I believe this, then I cannot be a dispensationalist.
On the other hand, I find Preterism as equally repugnant because it still misuses the idea of prophecy. Revelation is not a book written in 60 about 70. Instead, it is a book written at a particular time about a particular set of events. We find something similar in the Esdras apocalypses among others. They were coded messages of hope for a particular community against a particular threat. To say, then, that there were real prophecies is not accurate because it misuses the term and suggests that the author was not writing for his community in his time and place.
Preterism, then, is just as wrongheaded as dispensationalism.