In 5 mans Prayer of healing is nicer than COH unless i'm on the move with my group. I can just hit the button once and it heals a substantial amount. COH really shines in a raid setup because you can target other groups with it. If I wanted to use COH in a 5 man situation, i'd have to hit the button a few times to get the same amount of healing a POH would do, plus COH only has an 18 yard range (not exactly sure but i know it's smaller than POH)

I had improved divine spirit with my priest until I started raiding with her. COH is my favorite spell when raiding, but in 5 mans I stick to Prayer of Healing.