i go to a school that is h/p/f.
whether or not you are going to get stressed out about getting honors depends on what kind of person you are. for me, it doesn't really matter too much that it is h/p/f rather than p/f. however, for those people who are striving for honors, i'd imagine it puts extra stress on them. i was hoping to honor physio this year, and i definitely felt the pressure while studying for/taking the last exam. i guess it would suck if i felt that way about every class. but hey, i don't, so it doesn't really matter 🙂.
in the end, schools will know how you did b/c of the ranking system. so if you missed honors by one point, they will still see you did well.
some people in my class definitely don't have the attitude i have, and i probably would not have this attitude if i'd not taken several years off before going to med school or if i were interested in a competitive specialty.
if you are a super-competitive person who would prefer not to be, it might be best to go to a school that is p/f. however, i don't think there is a big enough difference between p/f or h/p/f to use it as a major criteria for choosing a school.