Not to "actually" here, but actually... while positron/electron annihilation results in just photons most of the time the situation with anti-proton/proton anni

Not to "actually" here, but actually... while positron/electron annihilation results in just photons most of the time the situation with anti-proton/proton annihilation is much more complex. Initially you end up with a bunch of high energy pi-mesons (you can think about this as the quarks and anti-quarks pairing off, which isn't really correct since typically more than just 3 pi-mesons result from an annihilation, the typical number is about twice that). These then decay into showers of other particles. Photons, certainly, but also leptons/anti-leptons (muons and electrons) and neutrinos. In terms of intensity you are absolutely correct though.