The frontal shot can be very deadly with correct bullets, a jacketed hollow point might hate this view. I've used it several times with great success. If I were pinned down to one angle I'd opt for somewhat broadside, I just want my slugs to be lined up with vitals on the backside, one of Elmer or Veral's finest will take care of the rest.
Twice I've shot through deer length ways, once facing me, the other time the deer was facing straight away & watching a coyote, the Keith slug whacked it in the right ham & exited the left front shoulder, good bullets will do that.

Dick