I have a 80mmED , I really enjoy using it visually in tandem with my 10"SCT and for imaging its a life saver for your sanity as you climb the rocky road of astrophotography. As a second scope that offers the imaging angle its got to be one of the best buys out there but I agree with the other guys aperture rules , for your one and only scope that is
I can't resist not putting a CAT amongst the Dobs how about a 8 inch SCT new or used , offers aperture and portability although you'll need a EQ5 mount at least to mount it