Digital BW, The Print

Diane,
here is advice perhaps not even worth 2c, and also against the grain
of the replies thus far.
My last (of 3) 120 cameras/systems was sold 18 months ago (SL66 with 3
Zeiss lenses, wonderful!). 
The difference is that now I have very much more depth of field for a
given image quality, no struggles with scanning and no dust spots (wow
yes!). And, mainly, *much better prints* (but I don't print 40x60).
The quality issue is fundamental - sensors are many times more
sensitive to light than any film, in some styles of photography this
matters, in others it matters not at all. 
Whether 6x7 is right for you depends a lot on your photographic style.
 It is not clear whether you have used a 120 SLR before but it is
certainly worth trying one on your normal subject matter before "going
for it". 

Good luck!
Ken