When it comes to contrast,  do you prefer high, medium,  or low contrast for B&W film?

Ilford HP5 has a medium contrast. Not as strong as the Tri-X 400 but definitely more contrast than Delta 400. ...however, that doesn't mean HP5 can’t produce an image with very high contrast.

Contrast often has less to do with the film and more to do with the light conditions and how you meter for that light. These early morning scenes had very dynamic light, dark shadows, and bright highlights. They were metered for the mid-tones/natural grey which will result in higher contrast with most B&W film.

If these photos were taken in even light there would be less contrast which would result in more shadow detail...

... which is good to keep in mind when planing to photograph a specific scene or person in a specific location.

We feel the high contrast makes these photos stronger. 

I you want more shadow detail and your focus was to take portraits, you would want to shoot in more even light or even the light out with a reflector or flash.