It really depends on what your plans are. If you're looking for a high RPM road race car, then a boat anchor like the 5.4L would be rediculous. Even an n/a lightweight drag car would suck balls with a 5.4L.
I really still think the 5.0L will be a reasonably easy swap once the first few figure out the details. This isn't the first engine swap. The modular/fox swap has been done for years and there are a LOT more nightmares involving that swap than this one.
A couple wiring diagrams, and some custom brackets and I think this swap will be cake (as far as swaps go).