8" Apeture will give you the light collection in any scope, so to get same or better you will need to get the same or better apeture.
The next is to consider focal length, The scope you are looking for usually have a longer focal length to a DOB although not all the time so magnifacation will be a bit more.
Since starting I found magnifacation is not the key as there are some really good views in wide field. Planets though would be better viewed in higher magnifacation.
Goo luck with your search or like me get a staion wagon
