3, partly because is actually fun to 100%, the extra abilities give enough extra mobility to Crash without breaking the game, the boss fights are a big improvement over 1 and 2's in terms of engagement and keeping momentum at all times, the camera was placed well enough even if going back is still a pain in the ass, and the variety of levels was nice.
Started 4 recently and is somewhat disappointing, is pretty frustrating to attempt to complete levels, hate the on rail sections, feels like there is some input lag every time you try to do something in those and the visual clutter and angles in those makes it hard to make out boxes and the like. The platforming itself is fun, but the levels feels longer than they should be, Crash isn't particularly inventive so making levels feel super long isn't a great idea, it could probably justify itself if they used the masks more. Still a fun and challenging game, but a step down from 3.
The worst one is definitely the N.Sane Trilogy version of the first game, their attempts to make the physics match 2 and 3 makes a lot of the jumps harder than in the original.