Hi Carl,
Betacam is sometimes compared (in terms of picture quality) with DV, and thats true,
but this doesn't means that because you end up in Betacam, DV is good enough.
I have no experience with the F900, but I work with an EX-1 and normally i end up in SD.
I would record with the EX-3 at 720p 25 or 30 (PAL or NTSC). Edit native or capture as Prores (no necessary). Render to Prores.
The EX-3 have an overlay that helps to frame for 4/3.
rafael
http://www.nagavideo.com