Glen ,
I've seen a 130mm apo last year on a DM6 set up for push-to, it was a very nice setup. And on Saturday night someone had a SW 150mm mak on an M2, which I had a play with.
In comparison the AZ8 is distinctly les solid than the DM6 and M2 however the reasons I bought the AZ8 were:
a. Two scopes side by side (130mm APO and 180mm Mak)
b. A high resolution encoder kit is available from Astrodevices,
c. It has clutches and worms to provide fine movement when viewing at high power. The M2 DM4 and DM6 don't.
Another alternative is the AYO Master
http://www.aokswiss.ch/ayo/ayomaster...ayomaster.html
Lastly the other mount I looked into was the TRex, but that's no longer available.