It always struck me that perfect pitch is more of a hindrance than a benefit. It would be like constantly noticing that you didn't start facing north every time you dance.
It's much more of a pro than a con (once you've trained yourself to utilize it of course), although there are certain situations where it can be a hindrance compared to not having it.
I find humming/recalling something in a different key more difficult than someone who isn't pitch perfect, because my mind is trained to recall it in the original key. Even with the great sense of relative key, it can be jarring to shift it on the fly. I can do it easily enough, but it just requires a more conscious effort.
Whereas a normal person remembers it in relative terms rather than absolute, so it's much more natural for them to do so.
Also it makes it painful to watch PAL region movies.
Aside from that, it's mostly very helpful, as long as you have the musical knowledge to support it. There are situations where I don't know how people do without it.