Hello,
My experience with the GOTO Dob is its awesome for planets. They move very fast under magnification and tracking or hand controller is my preferred way to view the planets. For objects outside of the solar system not so much so, they are fairly easy to keep in view.
If you had a dedicated planet scope I would say you might not need goto on the Dob - setting circles/argo navis instead.
I looked at the specs for the 8" SE and its 5.4kg OTA, 5kg for the mount head and 4kg for the tripod, total weight 10.8kilo(14+kg). (I know but that's from Celestrons site). A light weight 12" Dob from ES is $3.2k new and weighs in at 20kilo for the base and mirror(+8kilo the rest), the SW 12" GOTO is 20kg base and 23kg OTA.
Glass gets very heavy pretty quickly. At this moment you have a scope you use a lot, try and hold onto that as a feature for the next one. The best scope is the one you use.
Can you make it to Brisbane for the second hand market?
Steve
The link below talks about what you can expect to see from entry level telescopes... from really cheap to 250mm newts.
The medium example is close to your telescope and gives a 10" newt as large not the 12" suggested here.
http://www.deepskywatch.com/Articles...telescope.html