I have a '94 F250 N/A diesel 4X4 and it is an excellent truck. I agree you could get more zip out of a power stroke but you DON'T need it. I have 170,000Km on it (it's my baby, not a plow truck) and then engine and transmission have never been touched. The tranny did go into limp mode when it was less than two years old, the throttle position sensor went bad and it was an easy fix.
I have had the pleasure of towing a loaded horse trailer (filled with wood working equipment ~7 to 8K) and other comparatively heavy trailers and I am very satisfied with the power.
Empty I get 19+mpg (imperial), with a full bed it gets 17. I have not pulled far enough to get a good read on mileage with a large trailer but I would estimate 14 -15.
The only thing I don't like on this truck is the injector pump; I think Stanadyne made a lousy pump that is the Achilles heal of an otherwise (IMO) perfect truck. There may be rebuild options for this that resolves the flaw.
If the truck is in good shape then I would go for it. If you need to you can always replace the transmission, you still have less invested than a new one. I hear that some of the TX rebuilds fix some design weakness, I will certainly look for that when I need to change mine.
You could always get a Dodge with a HEMI
