I only use Fomapan 400 (and 200, and 100) in medium format, so my impressions are limited to MF.
For me, the comparison is between Fomapan 400 and Kodak TriX. I tend to prefer Foma 400 to TriX, depending on the look I'm after. Fomapan 400 is a wonderful film in the right developer (I use Fomadon LQN and expose at 320 EI). I love its rendition in the reds, and I find its shadows go black in a more legible (less expressionistic perhaps) way than with the Kodak TriX.
HP5? I tried it, but consider it inferior to the above two, because it's, for me, unremarkable. A lackluster film in medium format, IME - though I'm sure things might be different in 35mm.
Bottom line: buy a couple of rolls of both, try both, see what sticks.