Were they able to get the 460 to meet the latest emission standards? That might have been one issue.
We had an E350 van with the 460 and also have some E350 vans with the V10. The V10 is better from a drivers perspective. Since we never had any trouble with the V10's and I don't have to fix them anyway, I can't say whether they are more trouble to work on. I know we got
250,000+ miles out of two of them without ever doing anything but regular maintenance and they were still running like new. The 460 did the same.