The 5.8L is a good, long lasting motor.
The 5.4L is better and even longer lasting.
I had a 1994 and over 250,000 miles it never had a motor problem, but you could tell the motor was getting a little tired. It did need a lot of work on everything attached to the motor.... needed plugs and wires every 30k, thermostat by 150k, wire harness repair for be o2 sensors, a couple of sensors failed. Nothing show stopping but still needed plenty of TLC in the driveway.
My dad has the 5.4L. Needed plugs at 120k and 1 or 2 coils. And did one transmission fluid service after overheating the trans trying to back the boat of a steep driveway. That’s it. But it only has around 150k now.
I’d say the 5.4L is far less needy, but the 5.8L is a bit easier to DIY, except that now they’re all old enough plan on any bolt being stuck and breaking off.
FWIW, my V10 (which is the same as 5.4L with 2 extra cylinders) only needed spark plugs until needing some coils around 375k then a timing chain at 415k. Also had some injectors taken out by water in fuel around 350k. I did burn up a valve seat at 456k towing the trailer with a plugged fuel filter and a hot tune, and at that point I put in a reman because it was only slightly more than pulling the head for reconditioning. I scoped it to diagnose the compression issue, and honing still looked nearly new. I do the transmission fluid normally every 100k using the bucket flush method, with the pan coming off to replace the filter at 150k and 450k. Now has 495k.
2000 E450 dually V10 wagon