I've owned the Thoth (3 Magus version) for several years and it's been languishing in my unused drawer.
I just purchased several "companion" decks - a second 3-Magus deck (because it was sitting on a dusty shelf in an old shop), the large Green box (& a spare - I will trim one of them), a blue-box small (& a spare because they are cute), a Liber-T, and Anthony Clark's Ceremonial Magick Tarot Set (because it looks old and is supposedly related to the Thoth in design).
I also purchased two books - Duquette's "Understanding..." and Banzhauf's "Keywords..." These are VERY different!
I also got Scion's wonderful PDF file about the Liber-T, which looks absolutely fascinating!
Anyhow - I am getting ready to dig into the Thoth & it's friends (Liber-T and Magickal), to whatever degree and depth makes me happy - I doubt if I'll worry too much about really trying to memorize too much, or research too much. But I'm looking forward to whatever level this type of deck has to offer (artistic, inspirational, historical, etc.).