Rust is still an issue with them for some strange reason with older versions seemingly incredibly resistant to normal rust proofing measures as well. Can show signs of rusting from three years on. I know two people with a '54 and a '56 that have both had problems with the ecu. The '54 is currently on it's third, first two replaced under warranty but third was £1,200. Flywheels are dual mass from around 2000 on, you can pay up to £900 for a replacement from Ford (cheaper places are available) and I know of one Tansit that's had three in 100,000 miles.
Aside from that they wouldn't be the best selling light commercial in Europe for 40 years if they weren't any good and probably all modern vehicles cost loads to fix anyway.
Find a good one, look after it and you won't go far wrong.