While I have no experience with Passport America's mail forwarding service, I have used both the Escapees RV Club's and FMCA's mail forwarding services. Each of those services have forwarded my mail flawlessly during the past 6+ months for the Escapee's service and over the past 2 years for FMCA's. My mail and/or packages have always been received when & where I wanted. You do, however, need to be a member of each club to use their service.
Like Dixeray53, I get everything I can delivered on-line or by e-mail. But there are some things that I prefer to be mailed, e.g., magazines (not much of an on-line fan for these), and some things that require mail delivery, e.g., yearly income tax and health insurance information, vehicle registration forms, etc.
2008 Tiffin AB 35TSB W24, 08 Honda CRV
Blue Ox Tow Bar & U.S. Gear Unified Tow Brake