DISLIKE, very much. Tried it a few times, and the mana recovery sucks ass, for the same HP penalty. Either reduce the HP penalty, or improve the mana recovery, not sure who thought this one up, but they need to re-evaluate it.
Finaly got DB and other then the Mana Regen being a little lower then I would like its not to bad, only when I'm in grp do I have to ask for a Heal Over Time (HOT) from Cleric and that seems to keep my HP up so DB doesnt kill me. With DB, I havent been calling med breaks evry 4th kill in the new zones.
Pick up Reluctant Benevolence when you can. Using this in conjunction with DB is just silly. Especially if you can max RB out, as it lasts as long as its cool down timer. And it procs. A lot.
Base heal is 7k I want to say, and I have it crit for 14k when I trigger it. I always snag a neck item with a healing focus, so I might get more out of it.
I don't think heal focus modifies the heal from a life tap. I could be wrong though.
Unless it has changed it doesn't. In general, no worn foci affect any AAs (this is why all spells turned into AAs have a shorter duration, see aa snare for example). All of the spell lifetap health is coming from 2 places: the damage done (so for normal LT this would be your magic foci) and the crit heal (an aa--thus not affected by worn heal). For RB we are just talking about a proc, so also not focused by worn (only affected by AAs).
In groups with player healers, odds are you arent using all of your 12 spell gems...probably have 6-7 DoTs and a couple utility loaded? Consider adding swift lifedraw on one of your not needed gems and use it instead of flashblaze when you bloom. It gives you 2529hp/tick that gets extended with innate AA; takes a heck of a dent out of bloom damage.