I too have an RB67, and for the most part I don't find the 1/400th a problem and love the fact that you can still use flash with it. However, I also do a lot of air photography and there the camera really doesn't cut it. I use a Pentax 67II in the air, but that can only flash sync at 1/30, so as always its horses for courses. As for using 3200 ISO film in bright light with the RZ, no problem: get some ND filters.

David.