Pros and cons for Crash:
+All games on the game card.
+No irritating recurring framerate drops like in Spyro.
-First game is mediocre.
-Levels that have you running toward the camera are annoying, and so is backtracking in regular levels if you feel you've missed something.
-Quality of individual levels can be very inconsistent.
Pros and cons for Spyro:
+All three games are good.
+No absurd difficulty spikes or bad levels like in Crash.
-Publisher cheaped out on a 16GB game card.
-Irritating framerate drops even in spots where they are inexplicable.
Spyro was better back then and it's still better today. Even the worst Spyro game of the trilogy is better than the best Crash game of the trilogy, so it's an easy call. But Crash is definitely the better port to Switch.