If I were in the market for a new TH I'd first decide what I can pull with my current TV. Then type, ie do I need to still have access to my bed while towing (bumper type), if not then no question 5er (actually for me this is a done deal, I'll NEVER go back to a bumper pull). Once that is established you need to ask where you're going to use it and what would be the length limitations. If you're a state/national park person then you need to keep it 30' or less or if you boondock down nasty roads (another consideration on bumper vs. 5er). The floor plan.
That would be my process.
