What are the advantages of each and which ones to your guys/gals prefer?  Is there a visual advantage to a thicker mirror or are they about the same?

I was thinking of upgrading to an 18" dobsonian reflector. The StarMaster 18" telescope seems a little more portable than the 18" Obsession. I can't lift the Obsession 80 lb mirror box. I'd need a trailer or truck to haul the 18" Obsession.
Which would you guys/gals pick and why?

Debbie