You probably meant *E* 450. The F series is the pickups and other trucks with pickup noses.
I don't have one, but you'll hear from members here with high-mileage Class C's, some from rental retirements, and we haven't heard much bad about them.
IMICHABOD has a long thread dedicated to ex-rentals. carringb has an E350 with over 400,000 miles.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB