The S5Pro is quite old and has *a lot* of idiosyncratic quirks. The form factor is almost identical to D200 and accessories like 10-pin devices (GPS, remote release etc.), eye cups etc. will fit. However, the similarity is just a thin veneer. In fact, batteries for the S5 look exactly like those of the D200 and can be charged by the very same charger, but you cannot swap batteries between the two cameras at all. They simply refuse to power up the camera claiming they are "depleted". Put the battery back into its native camera body and all is well, though.
The most annoying issue is of course the peculiar Fuji sensor and the weird RAF (raw) files that most software either don't understand or cannot decode properly. Although the camera is claimed to be 12 MPix, the effective pixel dimension corresponds to around 9 MPix due to the unique sensor design comprising small and large photo sites in combination. Thus I would hardly recommend this model as as the best entry into a world of digital photography.
Despite the above, it is a nice camera that handles quite well unless you call for superspeed operation. The files even up to 800 ISO and on occasional even 1600 ISO are useful. My S5Pro is converted to "broad spectrum" and replaces the S3Pro UV/IR Limited Edition as the S5 has a better view finder, much better battery technology, improved EXIF recording, and finally, GPS support. The latter feature is very important to my use of the camera.
Like the D200, the S5 needs AI-modified or native AI/AIS lenses. It cannot deal with pre-AI variants. It also works with old AF/AFD lenses ('screwdriver' type) and more modern AFS(G) Nikkors. The very latest 'E' Nikkors will mount and function, sort of, but there is no aperture control at your disposal, so some nifty tricks have to be introduced if you wish to take advantage of these latest-generation optics.