I have that telescope (gs680) and for what you are paying you are getting a good deal. the quaility is right up there and it will last for ages. being a dob it is easy to use... if you get an equatorial mount you have to deal with polar alignment which can be a real turn off if you are new to it.
the GS is, i am guessing about 15kg all up but with handles it is easy to carry. anything on a tripod is probably going to be awkward.
skywatcher also make a 8 inch dob. have a look at myastroshop.com.au for them.
hope this helps a bit
