Ray,
First of all, welcome to IIS.......
I see you are not far from me & a few other members who also live in the valley. I myself am in Toowong, but I go to a dark site in the valley.
If you are wanting to look through some larger scopes as part of your decision making process, I'm happy to bring mine out one night.
I have an SDM 20" GO-TO & a Skywatcher 12" GO-TO.
The latter courtesey of the winning raffle ticket at Qld Astrofest.
The SW is the standard proprietry system. These units do not have a releasable clutches, so you cannot "push-to". It can only ever be driven by the motors. To be totally honest I think this is a bit of a pain, but hey, who am I to complain......
The SDM is guided by an Argo Navis unit which tells the Servo-cat drive system where to drive to. The SDM can either "Push-to" or GO-TO so you can have a go at pushing with the aid of the Argo Navis.
In answer to your question, I'd go SDM all the way.
http://www.sdmtelescopes.com.au/
But I am a little bias..
