Things have changed now that my lowly priest has gotten the Chakra and Revelations talents. The Chakra has too different modes, the Serenity Mode, which is activated by casting Heal after hitting the Chakra spell, and the Sanctuary Mode which is activate by casting Prayer of Healing (and Prayer of Mending but that's a level 68 spell). Each mode lasts for 30 seconds at which point you have to start it again. (There's a talent State of Mind that can be used to extend the time of the state, but I don't have enough talent points for it yet.)
In the Serenity mode a Heal will reset the Renew duration on the Heal's target. It also adds 10% extra crit on all direct heal spells. It's my Chakra of choice at level 55.
The ability to keep a Renew spell running just by hitting the tank with the very mana efficient Heal spell is great. I have enough mana regeneration to spam the Heal spell. This keeps Inspiration up on the tank, and procs Surge of Light for free Flash Heals. If you have an aggressive DPS that likes to off tank, keeping up renew on two targets is pretty easy.
The Chakra spell itself does not cause a GCD, so it can be added directly to a Heal macro. Such as:
/cast [@mouseover,help]Heal; Heal
The Revelations talent changes your Holy Word based on Chakra mode selected. In Serenity, it becomes Holy Word: Serenity. This is an instant heal that increases crit heal chance on the target by 25% for 6 secs. Obviously a great spell if the Tank is going to be slammed with big incoming damage or a DPS pulls aggro and will need big fast heals to survive until the tank gets control back. The problem is that at this level of healing, nothing is hitting tanks that hard and DPS can be saved with a shield and Flash Heals. I also really liked the ability of Holy Word: Chastise to interrupt an NPC casting a nasty spell.
Also, there's a bug which makes a simple mouse over macro impossible with the Holy Word spells. I have to select the player to target the Holy Word: Serenity spell. It's a very annoying for someone that's used to mouse over healing, and I hope it's high on Blizzards to do list.
The Sanctuary Chakra is a lot more spectacular looking, with the big white AOE heal on the ground, but it's pretty pointless at this level of healing. Except when pulls go bad...
Prayer of Healing
Binding Heal + Serendipity + Prayer of Healing is a life saver when pulls go bad. Imagine you're in the Grim Guzzler and suddenly all the patrons are attacking. You plant a Renew on the tank and 15 "Change Targets" flash up, the Mage starts spamming Arcane Explosion, and the Tank is turned to the wrong direction, trying to figure out where to spit his Cud. Binding Heal, keeps you and the target with the lowest health alive and makes the next 2 Prayer of Healings go fast. Rinse and repeat. BH, POH, POH, BH, POH, POH, ... The party will be amazed when everyone is alive afterwards. The 15% heals from Chakra Sanctuary can't be discounted in this situation, but in general this shouldn't be happening very often.
Next I have to decide, do I take the Circle of Healing talent or the State of Mind talent. Circle of Healing seems like a great spell in theory, but with the long cool down, I'm thinking its more of a Raid talent then a low level healing talent. Where as with State of Mind, all I get is the ability to extend the Chakra state that doesn't really take any time to restart.