I have an 8+ so I can use the same set of effects.
The original portrait mode that works on the 7+ as well is ok, I sometimes take good pictures with it and I printed some of them. Usually if you zoom in you can see the face has been cut from the background and something like hairs or a little pice of the ear is missing, but if you look at the picture from a distance it seems pretty good.
Sometimes I try portrait lighting effects, but I'd say I can get a good result 10% of the time at best. The b&w pic is really great, but only seldom works and I never printed any of those pictures. I know it is software related, so we can expect improvements in future versions of iOS, but now it is too frustrating.