The following is my opinion on end-game raiding. Not looks or anything arbitrary. I feel I have to make this note as my intentions were not clear apparently. This is my preference leaning towards a build centric around Determination followed by Spell speed with crit being lowest priority. It is the general consensus of end-game raiders that Determination trumpts Spell Speed in stat stacking for healers. My advice below is geared towards those that wish to get the biggest upgrades (stat-wise) and spend their myth efficiently.
Please... Please... Do not waste your first 900 myth on AF2 chest.
The AF2 chest is not BiS, Determination is much better than spell speed. Also, the people I see who have a simple relic and AF2 body make me cringe very very hard.
To reiterate:
AF2 body is not a great FIRST upgrade ( it's not so bad if it's your 10th week of coil and it's your ONLY upgrade because you can't get the damn tunic to drop. )
If you are looking for an HP/Healing upgrade the Relic+1 is far superior. Disregard this if you never intend to complete coil content, obviously you would get all AF2 as you will never obtain Allagan pieces.
below is my myth tome spending guide that I made/followed:
-Thryus +1
-Hero ring of healing (because strategos never dropped probably save for pants here)
-Cleric's Culottes
-Cleric's Boots
-Cleric's Gloves (many argue that vanya with melds could be better considering your choices are between SS and Crit on this slot)
There are several slots were you will not have an option for Determination. Those slots are up to the person to decide whether they would like crit or SS. If you decide to go Crit most of the AF2 Jewellery is crit and allagain is determination and SS.
That should conclude all myth tome purchases and if for any reason you would continue to get AF2 at that point is if Coil RNG isn't favoring you ( 10 wks with out Tunic of Healing dropping :\ )
Thanks for reading and happy hunting.