I started with a F801s in a Subal housing. I've still got it, and two working F801s bodies. They're worth much more to me as a back-up housing than I could ever get putting them up for sale. I plan to be using it again this summer while my S2 and housing are both being serviced.
You can take some great pictures with a F801s in a miniflex housing. Subal ports are very good, particularly the big dome. I think you'll find that the F801s autofocus works adequately for anything except hypermacro, which is true of newer cameas as well. Synch speed isn't the fastest, but it's not a major limitation either.
Be careful loading film into the F801s. They have a tendency to jam mid-roll if the film is misaligned when loaded.
Don't worry about paint chips or scratches on the outside of the housing. That just shows the housing has been used and loved. Do inspect the mating surfaces where the housing closes and the o-ring groove for scratches, dings or corrosion, but I'll bet you don't find any problem.
The bolt closure system on the housing isn't the fastest or easiest, but as long as you take reasonable care, it works well. The biggest disadvantage with the housing I can think of is that - if you use a tray bolted to bottom of housing to mount strobes on, you pretty much have to remove the tray before opening back of the housing.
The Miniflex normally comes with a single Nikonos-style strobe port connection on the upper left, but there is a plug on the bottom where you can install a second strobe port. This is worth having done, giving you a built-in back-up if the main port packs it in. Be very careful removing the Nikonos plug - make sure all is dry, tilt the housing so that the port opening is facing downward as you remove the plug, and immediately swab the inside of the port with a Q-tip or similar. There are spring-loaded pins inside that will seize up immediately if even a tiny a drop of salt water gets in. While on a trip, leave the cable in. (This is not specific to the Miniflex - lots of new housing use this Nikonos-style strobe connector, but if you haven't used a housing before, this is one of the classic weak points in many systems.
Frogfish