Made a couple of these for my rogue.
Tested on rats out in the vale, proc rate on the life stealing seemed to be about the same as Dreamspitter is now, every 3 or 4 crits.
For reference, I was able to make the required shards at level 9 arcane and level 33 divine, using the +15% boosters. If I had actually bothered to level arcane I would have made better than +2 enhancement on the item.