WH chassis had more problems with the Bosh breaks and the 8.1 is considered less desirable because is not common and they have a history of internal failure. The same floor plan will be 10 to 15% cheaper with a WH chassis in the used market. The V10 pre-2001 had the spark plug problem. It was improved after that, and then completely fixed in 2005.
Transmission on the WH is better than the Ford, but the Ford after 1997 does OK.
Ford owns 87% of the gas market, that is why you don’t see too many WH.
I had a fleet and as a policy decided not to buy WH because I wanted everything the same.
If the WH has been properly taken care off, it could be great, but I would put some of the cash you save by not buying the Ford aside in case you have to do brakes. (Normally you need to replace calipers and all).