The F4 has a very nice "silent" mode IMHO. I can't speak to the F100, F5, F6, but used F4 bodies are cheap and built like tanks. The standard F4s with the MB-21 is pretty large and some people don't like it (including me)... So, if you can find it, the MB-20 grip is nice and small, takes 4 AA batteries, and the only things you lose are weight and an electronic motor terminal; the top motor-drive speed drops to 4 fps which is plenty. There are some lens compatibility issues on an F4: there's no support for VR, and if you have G lenses, they will not work in A or M exposure modes, only P or S. However, I use my Sigma 12-24 on my F4 in shutter-priority and it works out alright. As someone who started out with the original Nikon F, I do favor knobs and dials over buttons and the F4 fits the bill nicely.