I'd also like to know what "fast regen" means. Precisely what it means. (Is it double regen? Triple?)
Hmm...I've been struggling a little with getting good use out of Glowing Guardain post-nerf. Humility is still an excellent boon and makes me want to go Guardian. Buuuut I feel like if I'm going Guardian I basically need to save up 80 piety just so that I can use my potions. (Actually wait, if you have 80 piety, might as well use that 20 piety healing boon, as it's 50% HP/MP healing, so using it four times heals slightly more than 4x potion+4x mana potion). 80 piety seems like a lot of piety just to do something you were going to do anyway.
Although...hmm, maybe I've been doing it wrong; maybe what I should be doing is converting all the potions as soon as I worship GG. 8x potion conversion gives me 40 piety, I think, so I just need to get another 40 to get back to the amount of healing I would have previously had. This would also handle another aspect of GG I've been struggling with (having 0 peity when you start worshiping GG is scary; you really want at least 5 to start doing stuff).