I was fascinated by Dick Arentz work and was looking for something larger. I liked the idea of 12x20 because it was so much cheaper to cut the film down if I wanted a smaller image, say 8x20 or 7x17 than to buy the backs and film holders. Even now with film going from $4 a sheet for 12x20 to about $14 a sheet it is still a bit of a bargain over adding other formats.
I did a figure study workshop in Carmel recently where I used the 12x20 in the studio. The images are simply amazing.
Lens selection has been even easier than the 8x10 as I was able to find a 210 xl, a 355 claron, and an unbelievably contrasty 24" artar. I have a couple more but that really tends to be what I use with the camera. Due to only carrying one or two lenses it is easier to carry than the 8x10. What can I say?
It certainly becomes a performing art as well as a visual art when you get that beast out to photograph the land scape. I sometimes enjoy the stories I walk away with more than the images.
BTW, I went from buying packaged chems to 50# bags in 2000 when I started shooting with the 12x20. It has saved me a small fortune due to increased film developing costs.