if you can change out the bellows + rail as allen suggests,
i would keep the calumet in a heartbeat.

while the gvII is a good camera,
because the rail and bellows are
permanently attached .. you kind of have your
hands tied if you want to use much longer than a 210, or shorter than a 90mm ...
(not to mention the compendium shade for the gvII is not very easy to find )

have fun!