I already know, not many know the physics of this robe because they may have never had the chance to use a ton of Life Steal.
I'll share what I know.. It was great in the old welling and arena, and it's only gotten better now imo.. I've already used it after the update with Dion in game. Driving along.. welled over 50 items at a shot, continued to drive on when I was finished. I realized I never healed ONCE, or did I ever have to leave to shrine (just for more wells).
Before the update, it got used heavily, it's a shame I am not sticking around, because this robe hasn't seen the end of it's days still!
Put that in your juice box and suck on it for a while.
When you decide you're really interested in Magic Luck, take my advice on this robe. It did about the same amount of damage vs a 53str/3 life steal robe /w a dagger (after update ofc). It's phenominal. Especially when paired with my LS/ML/Dex charm!