I am extremely surprised this has not skyrocketed on all servers like Sorcerers Ring.
It's not hard to get this effect, and its very worth it. I pop off 256 cure3's every cast, with up to 320 in Limbus. I get 880~ Cure5's up to 1200 in limbus.
If you use Windower, just use my SpellCast plugin and setup and you can very easily get this effect 24/7 and boost your effeciency by a ton.
Configuration File for my WHM:
http://www.windower.net/wiki/plugins/spellcast/userxml/whm/aikar_whm
No extra macro hitting needed, you simply get the effect every time you cast cure...
Few WHM realize the importance of this item. At 75, mages have a large amount of HP > MP gear available. With some smart macros you can force yourself into latent hp(75% or less).
I love this ring as White Mage.
10min timer of Devotion help keeps the HP low, and you can always pop a poison pot to avoid the regen. Wear Zenith (head/hands/feet/legs if access to all) and any other HP>MP gear you wouldn't normally use (astral shield, asklepois).
As Aikar said, you do notice a big difference. And it's worth it.
I think it's also worth pointing out it's not a bad ring if your doing some soloing. If you need to cure, then I'm assuming your under 75% so why not get the boost when you do it.
Aikar......although we are from different servers i believe i speak for all users/buyers to not even make mention of price increases on this ring. it is like a hidden treasure for whm's with good convert gear knowledge for cures or good macro builds. shhh 6k is just perfect and price hike simply yells R-M-T
WHM has this thing called Auto-Regen. Makes it just slightly difficult to keep your HP where it's needed for the latent to activate. That's probably why it's not super expensive like Sorcerer's Ring.