Looks to me like the Ford has a new bed. Not all bad but Ford's tend to rust in the wheel arches. I'd take the 7.3 hands down (I have one) and the E4 is a good box so long as you maintain it, like anything else. The Mopar's box had issues back then. Overall quality will be higher with the Ford and the Pre-Tier 4 7.3 is always climbing in value. My truck today is worth more than half what I paid for it and increases every year.
I would not buy a 7.3 with a manual box. Had one as well. Fine if you want to play truck dricer, not so good as a consumer oriented transmission.