I've just started reading with the Thoth. It never used to interest me before, but suddenly it called to me; Shouted, actually!
I put it on my Amazon wishlist, and within a week it turned up at my local used book store (hadn't been there the last time I was in)....
Like it was meant to be!
I agree with the more experienced readers on this forum who say that you can read the Thoth intuitively, right out of the box. BUT your readings will probably be much deeper and more informative if you're familiar with either/all the systems of: Kabbala, Astrology, Numerology & elemental dignities. This is true with any deck, nor just Thoth, but with Thoth the references to other systems are much more in your face.
People say that Thoth is a dark deck, but I feel it is just really honest and perceptive.
To some, this probably IS the scary thing about it!
I see Thoth as a deck for intense, honest self-examinations, but I can also see it being brutally direct when Querents are in denial, or keep asking the same question over and over.
In fact, I think I've just found a secret weapon for those times:
"Oh, you want to ask about you ex boyfriend AGAIN?!?!? Well, Ive got just the deck here, it is called the Thoth...muahahahaha!"