Hi Houghy, I can't comment on the saxon ed80, but I have the Zenithstar 80 which is same as the Orion Express. You might find the WO version just as cheap if you want a diagonal - I got eh ZS80, 2inch dielectric diagonal and a minus violet filter for $ 8 hundred and something from Frontier Optics. Very nice, beautiful build quality and lovely views. There a few pics taken through the Megrez 80 (much the same optics) on the ATS web-site that deom what can be achieved imaging through it too.
http://www.atscope.com.au/williamopt.html
enjoy your consideration/purchasing!
cheers,