GH song is a nice time saver, but not much more then that. I dont see any reason to do more then scroll GH. It lasts 12 min, and costs 0SP, no brainer in most situations for me. The song just saves time, in simple raids like shroud, where you can sing it once or twice and be good to the next shrine.
The IR song is a fantastic DPS boost in melee groups, and I use it most of the time.
More HP is great
Med Armor is over rated, but does open some good options ( ie Epic Marilith Chain and Epic event armor)
Weapon prof is nice, but most WC splash a few levels to get this earlier anyways.
Over all, great 2 AP points.