Well, of course, it depends on what you want to do with the scope. The most frequently used line to answer this question is the best scope will be the one you use the most. So have a look here:
http://www.iceinspace.com.au/63-260-0-0-1-0.html
Go to a good astro shop and ask to see some of the equipment (the GM-8 you mentioned is actaully a mount not a scope!) and if you can go to a viewing night with your local astro club, you will be able to look through some of the scopes and see what you can do with each type.