What makes it your favorite game - or more accurately (I hope) what makes it your favorite setting? I'm always down to get inspired by awesome settings.
Short answer: A rich density of imagination.
Longer answer: Talislanta is a truly "exotic" fantasy world with few, if any, real world analogues. There are dozens of races and cultures, each of which is distinct. The main timeline (all five editions, but not Savage Land) is set about a thousand or more years after an apocalypse. The main setting is the Talislanta continent, but there's other continents lightly described in the Worldbook. It is more Jack Vance and Clark Ashton Smith than the Tolkien/Howard of early D&D. It harkens back a bit to the science fantasy of the 70s, with a bit of a "disco" vibe. I see it in a similar tradition as other "non-traditional" fantasy settings like Tekumel and Jorune. If nothing else, it is a wonderful world to explore through reading...lots of great ideas.
Plus, everything but the most recent book (
Talislanta: the Savage Land) is available for free in PDF form on
Talislanta.com. The Savage Land is a new book that covers the time right after the cataclysm, and is very sword & sorcery-ish. There's also a 5E version, but I recommend the Tal rules to get the full feeling of the game.
If you're curious, probably the best place to start is the explanded version of the
Chronicles of Talislanta (link opens the PDF), and also the
Talislanta Worldbook, which touches upon the other continents. If you're interested in the game itself, the big
4th edition book is probably the most popular treatment.
For a deeper dive,
Hotan's History of the World covers the history and continent of Talislanta in depth, and the
Archaen Codex or
Codex Magicus have a lot of great lore. I'd also recommend checking out one of the bestiaries.