I ran a T&T campaign for many years. It is much more silly than most D&D, in terms of puns for spell names, lots of quirky dungeons and traps, and a chaotic assortment of solitaire adventures, monster books and modules. For some people that and the dice mechanics - d6 but you add and roll again on doubles - puts them off from playing it. The classes are pure California science fiction writer circa 1973 - Wizard (psionic spell caster), Warrior (NO magic other than items), Rogue (can use magic but in theory not as well as a Wizard, can fight but in theory not as well as a Warrior) and Warrior-Wizard (full powers of both Wizard and Warrior).
One thing that very much put me off is the almost suicidal bad business practices of the IP owners - bringing out new rules versions no one asked for, and so on. That's over now so there is a large range of classic and "deluxe 6th edition" stuff. But it's no longer owned by its creator Ken St Andre. He still owns Monsters! Monsters! though, which is T&T from the point of view of the monster races....