The best comparison is to Holy Rosary. Same cost, slot, tags, level etc. The difference is you're trading away 2 Sanity for possible card draw each turn. The question is then how often will you draw the cards? If you are doing chaos bag manipulation then this card is great but what about a standard mystic? That depends on the bag composition.
Its important to notice that you will succeed on a Pass or Fail by that number so to figure that out you have to do some math. First off it fluctuates due to scenario effect tokens having different values each scenario but I'll create a bag as an example.
+1:2 0: 3 -1: 5 -2: 4 -3: 2 -4: 1 F : 1
Find the number you want to succeed on, then sum the qty's above and below, then again, and so on. If you are trying to succeed on the -3 then you can call 0 for 2/18; 1 for 5/18; 2 for 5/18 etc... If you are trying to succeed on the -2 then you can call 0 for 4/18; 1 for 7/18; 2 for 4/18 etc...
Though the bag may be quite different from this its not unreasonable to say that you'll probably succeed 1/3 of the time. So now you're trading 2 sanity for an unreliable extra card every 3 turns or so. I think it really depends on your deck composition and if you need that extra sanity or not. If you're taking the spells that give you horror then I'd recommend the Rosary. If not, then I think I'd probably prefer the Pendulum.