The 45 is a lovely, lovely lens. I used one professionally for architecture for years whenever I could get away with not using 4x5. There's no noticeable distortion if you line it up correctly, and I had a grid screen installed to help with that. I sold the camera and lens when I switched to digital, and seriously regret not keeping the outfit.
I've found the best way to compare the field of view of different formats is by comparing side-to-side coverage. By that standard, the 45 is equivalent to about a 22.5mm lens on a 35mm camera, with a little bonus area on the top and/or bottom.