I considered Freeflow superior to Fiery when we had our 700. The only issue I can think is FreeFlow required yearly unocking code to function, though they may have opened it up at end of life when they no longer would provide service to the unit.
One Caveat, there was some auto image enhanceent technology that if activated could introduce artifacts to photos and documents. I found it better to leave that turned off and do any image manipulation at the desktop.
What I liked about the Freeflow is we could autoscan black and color documents, let us say 8 pages color 80 of black and if on auto you would have a pdf of 8 pages color and 80 black. With our previous Fiery on a 240 you either ended up with 88 pages outputting as color clicks or 88 pages greyscale so one had to manually fix the pdf inserting pages from 1 into the other.
After my retirement my printshop moved to a Versant 280 and as Fiery had taken over Freeflow it was no longer available. I never did find out if Fiery fixed the flaw so it could autoscan color and black into 1 pdf for proper click counts.
I doubt Fiery Command station can replace Freeflow Print server, we did have a remote freeflow software that could allow one to basically see and do what was being done on the Free Flow but being as the copier was close by it seemed as easy just to deal with it directly as it probably entailed changing stocks anyway. We did still have Fiery Command Work station for the 240 we kept to provide it with a more FreeFlow type experience printing to Process and hold so we could more easily release a document at the printer with proper paper inserted.
Are you limited to transferring pdf files by USB?
