The obvious disadvantages are that cassigrain optics tend to be fairly slow in the best of cases, and I'd need a lot of clearance out the back in order to bring the light cones together to the eyepieces. This, along with an (admittedly newtonian) bias I have towards small secondaries, would lead to high magnifcations and a fairly small field of view which seems definitely un-binocular like.
I'd probably buy the optics... Not quite ready to take the plunge, at least not on matched cassigrain mirrors and hyperbolic secondaries.
Any thoughts?
Bob