QUOTE(clarkiest @ Jan 10 2015, 21:13)

For reducing 1H reliance on potions, ether theft or spirit theft?
or raising divine/dark not quite worth the hassle?
Augmented Drain singlehandedly gave me the ability to play PFUDOR arenas indefinitely without the need for potions (and death due to running out). In my experience, nothing else has come close to its utility, other than getting 1 -> ~150+ supportive proficiency making it much easier to cast Cure. Oh, and switching to 1h/shield.
If you have low defenses/mitigation and frequently take significant spirit damage, definitely use Spirit Theft. Mana is replenishable via Focus, but spirit isn't.
I haven't tried Ether Theft, but I'm pretty sure it's not worth it for 1h heavy, since the mana returned looks like it would be barely more than the mana spent, even if you manage to proc Soul Fire on the first try.
The second level of Ripened Soul for Spirit Theft comes at level 300 and is a huge help. Usually you'll be using Disintegrate (level 2 forbidden) on a bunch of mobs at the beginning of a round hoping at least one will proc Ripened Soul, but before level 2 Ripened, the chance of a proc is only around 52%, in exchange for a mana cost significantly more than Cure. After level 2 Ripened, that chance shoots up to 79%. (assuming you have Better Disintegrate, otherwise chances are 41% and 67% respectively) So before level 2 Ripened at 300 you're taking a major risk on losing mana for nothing. The chances of successfully converting mp to sp might not be worth it unless your mp is nearly full. You might just wait until level 300 for level 2 Ripened and more ability points, unless you're feeling like you absolutely need the spirit now.
If you have top-tier equipment, you might have enough mitigation and bonus HP that you just don't need Spirit Theft, and you can just use spirit pots - that's how most high level people seem to play, but if you're like me and don't have great equipment, Spirit Theft can compensate for the significant spirit usage.