For those who own it, why do you like this deck?
Of course in first place for me is the artwork - the swirls and angles and art deco forms - even before you get into a discussions about what projective geometry might mean in esoteric terms. It is a deck which might have looked odd in the 1950s but which, (for those of with a taste for modernism/mid-century modernism etc) now just looks better with the passing decades.
Also I think because you know it will reward, you know there are depths that will connect you to other, greater things. It is tarot that takes you beyond tarot. I have a feeling with the Thoth that its energies take you beyond the confines of the card. I like that feeling.
With other decks, I sometimes have the feeling that however deeply I go, I will only ever go deeper into this particular deck. If I decide to dedicate myself to the Cat People - for example - I will only ever really get acquainted with the universe of the Cat People as envisioned by that deck and I question why I would do that. With the Thoth, I get a feeling of going way above and beyond a tarot deck. Having said that, so much of it eludes me and yet something in it urges me to go one because the next layer (what's that T.S Eliot quote, "like the layers of an onion"? All these analogies - pomegranate, onion.) will make things clearer.
And besides all this, even if you aren't hyper-knowledgeable about decans and Hindu mysticism and astrology and Egyptology - you can still read well with it. I think one has to be careful not to be intimidated by the erudite mists which hang around the Thoth and put people off. It's one of those decks you need to barricade yourself away with (with this and the Book of Thoth) and just not listen to anyone else. I'm a great believer in this.