Sean I think the dev time is a bit faster. I'm guessing it's the same as the 100b & c, the packs are thicker than Polaroid packs. I suppose for 29 bucks I could give it a shot in my 4x5 graflex back. Anyway, I'm planning on taking my back to the supply store and seeing just how much of a difference there us-if any.
have a 550 back - just am hesitant as the 100b & 100c (especially the latter) have proved to be difficult in other backs and expect the 100B45 100C45 to be equally temperamental. Personally I'm not up to paying for another back and will likely wait for the impossible project to release a 4x5 film - even though that wait may be a good couple or more years).....
If fuji was making pos/neg film that would sway me to buy their back !