This game ranks among the best of the Sword & Sorcery genre games that I have come across.
I don't consider myself "Old School," per se. I started gaming in '81 with Moldvay Basic (well, before that, but I was ignorant of D&D and was introduced to Holmes by an older cousin). I enjoy the older playstyles, but I am also a fan of newer games (Shadowrun, Rifts, the d20 products, Fate, Cypher, etc). I never read the prior incarnation of C&T.
This game pulls from some of my favorite source material: Conan, Elric, Weird Tales, Lovecraft, etc., The O.G. Dungeonmaster's Guide, Fiend Folio, Stormbringer, music inspirations that remind me of my high school days (old Metallica, Slayer, etc). Magic is powerful and mean (no saving throws, though player characters can "test their luck" to mitigate some dangers). The selection of beasts is a mix of Howard/Lovecraft and others. Magical treasures are reminiscent of Warhammer Fantasy (unique and often consequence laden). Corruption and sanity serve as balancers to the corrupting forces of black magic (yeah, I used corrupting to define Corruption. Big C vs little c. Just go with it, it works.).
What I'm saying here is: the game has an incredible atmosphere that the rules firmly back up. This is, in my opinion, the most important aspect of a game.
The system is based on Swords and Wizardry, but it is sufficiently different to make the purchase and play worth it. I am really impressed with the author and editor (I can be fairly pedantic at times). I am not one to point out when one uses "he" as a standard pronoun (mainly because, English), although I generally dislike the he, she, or he/she alternating between chapters that some games use. The author/editor chose the route that I generally choose: using words that are completely gender neutral. I feel it shows a more intelligent choice while not catering to a more vocal segment of society (please, no offense is intended towards anyone).
Other reviews have detailed the rules.
I would favorably compare this game to AS&SoH, another S&S game that I think is fairly incredible. C&T edges it out slightly, however, mainly due to ease of rules in C&T vs AS&SoH (Astonishing Swordsmen and Sorcerers of Hyperborea). I could see stealing from either game to complement the other.