Having had two of the Keystone Passport's cousins (Keystone Springdale and Keystone Outback), I've have good success with both my campers. Of course, we don't abuse them either and I'm constantly on top of repairs and inspections.
I've not heard very many negative things about the Passport, any of it's brothers or sisters (model numbers), but if it will help, Keystone has a forum. I became a member of it years ago, done lots of reading, but virtually no posting, as my "favorite" is RV.net!
Still it's a good place to snoop around if you're looking for real users:
Keystone RV Forums - click here.The "Prospective Owners" folder may also help.