Well, I won't have a basis on which to judge the quality of my particular copy of the 45mm, but I can't imagine that I'll be disappointed. I shoot 135 film stuff as much for the joy of the process as the quality of the results--I imagine my approach with medium format will be similar.
Incidentally, I don't typically spend a whole lot of time at the wide end...I was keeping my eye out for a kit with the WLF and a 90 or 105, but ended up jumping on this one since package deals with the WLF seem to be fairly uncommon. Anyway, this will be my landscape setup and I can add a prism and normal/portrait length lenses later for a "point and shoot" setup.
More immediate though, is my need to figure out my digitizing process. I "scan" my 135 B&W negs with my K-5II currently, and am generally happy with the results. I will have to see if my process is easily adaptable to 120 film or not. I have seen some people stitch together multiple shots of each negative for better quality, but I'll have to see if it's worth it for me to go through that.