I will paraphrase Paul's reply below.
He went on to say,
"Please rest assured that Yaesu does care about its products, their reliability and performance. We certainly look to resolve any problems as soon as they become known to us. The FT450D is a splendid radio, having done excellently at the T32C DXpedition last year when over 200K QSOs were made with no reports to us of any hum problems."I thought this was an excellent and totally professional response. Yaesu is a first class manufacturer and it is reassuring to see they have taken on board the hum issue in this otherwise excellent little radio and have now taken steps to properly fix it on new build units.