We operated a Golden Eagle throughout Europe and never experienced the problems that others did with the engines. I found it an excellent rewarding aircraft to fly with a great cabin and very quiet but the wheel spin up on touch down produced some 'orrible' passenger moments sometimes.(standard U/C)
Our aircraft was replaced with a Citation so if you want to know about operating cost pm me and I will put you in touch with the ex MD who handled all that.
The only incidents we experienced in the 8 years we had it were.
Engine dipstick fractured in situ
Struck by lightning twice (one incident cost £20,000)
I seem to remember there were some C421 incidents with the fuel pump systym--my memory is dim but I seem to remember there wasa 3 position switch and one or two pliots had the wrong selection on TO. I think--worth finding out about.