I dont have a log to back any of this up, sorry for that, but I think you can verify most of it by using logic.
First of all, it's not possible for a DPS class to take the blue buff. It checks based on spec, so no cheating either.
Red: pretty good for everyone, but it does NOT boost PW:S, making it worse for discipline. Beside this its a simple +100% healing on everything (includes HoTs). Between holypriest/druid/shaman/paladin its pretty much equal, but because the other buffs favor other classes you will probably want this on a druid.
Green: this does NOT work on HoTs, and the healing uses a new spell (Essence of Dreams), meaning it will NOT proc anything that is related to the spell you used. For example, if you PoH with this, it will duplicate and distribute the healing, but the DA part will not be amplified. This skrews druids and discipline most, making this best for paladins/shamans. In 10m, with 2 healers, you want to put this on whoever doesnt take red.
Blue: a lot better than you might expect. This is pretty much the bomb. 75% reduced mana means you have infinite mana, or at least I cant think of a way to possibly go OOM with this. 100% haste puts almost all your spells at 1s cast.
Sidenote on how haste works: the basic GCD is 1.5s. This can be reduced by haste, but only down to 1s (known as the ''GCD cap''). You will easily reach this with the blue buff. For priests, PoH will be reduced to 1-1.1s depending on your haste from gear.
This means that whoever has blue can cast any spell in 1 second for no cost. A discipline priest casting PoH is very sick for this, a paladin with Holy Radiance or shaman with Chain Heal slightly less so.
Personally we will go with Druid+Disc for heroic 10m, putting red on the druid and green then blue on the priest.