Pro 400H has dropped darker tones on me so many times.. even in even lighting has dropped out dark hair to simply nothing.. Portra 400 has never failed me. In terms of grain Portra 400 is significantly finer than 400H I've found. An optical 8x10 from 6x7cm Pro 400H, and Portra 400.. the 400H looked like it was from 35mm. I could never go back to 400H.
I never had much of a problem with 160S, really liked it. I do prefer Portra 400 to Portra 160 usually.