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.
2019 Navion 24J