The original NES (ntsc) Tetris relies on the perfect blend of input timing, pattern recognition, adaptability and quick decision making. Practically every Tetris iteration since has scaled back on the importance of these core principles in favour of ease of use and casual playability. The exceptions to this would be Tetris Grand Master, Tetris IO and a few others designed with competition in mind. I never played Tetris 99 but by all accounts it was a great version designed with fun and mass interaction in mind. The original Game Boy version is good too and it's the one I grew up playing but it has a few major limitations.
The original NES version is still recognised as the best standardised version of the game. The lack of input lag on NES hardware and crt tvs is another benefit over most modern editions.
I don't play much these days and the scene has developed a lot in the few years since I dipped out. Bizarre grips and multi tapping techniques were developed to overcome difficulty resistances, allowing players more time and greater piece manoeuvrability. Meaning scores previously impossible to attain. I can still hold my own in a traditional game (DAS) but what the STEMbrained children who took over the scene are doing now is really out there.
Ecstacy of Order is a great documentary on the original Tetris scene if you want a good overview of where the competitive scene began.