James, I've had several 8" scopes but I just got a 12" dob and it just sucks in so much more light and the views are so much more vivid it's fantastic, but. Mounting that 12" beast on an eq mount to take photos is really hard. I need tube rings from the UK and now we are talking big bucks just to get them here.
If I did it all again, I'd look for a 10" anything on an eq6 goto. Then worry about comma etc etc later. How much do you have to spend? That sort of sorts out the problem