The original trilogy has always been much better in my opinion here are my main points
Lightsaber fights - The lightsaber fight between Luke and Vader showed so much emotion and you could feel the tension in the room and feel the fear Luke had just from his emotions on his face
Writing/exposition - The writing in the original trilogy is bounds and leaps better than the prequels and the prequels have much more exposition in the movies (I&II mostly)
Acting - The only gripe I have is Anakin's casting choice for the actor, the rest were great
Blue Screen - using actual models in the original trilogy for special effects has in some cases (exception of most of III) looked better than CGI effects in the prequels imo
But overall enjoy the prequels however find the love arc in episode II boring, making AotC my least favorite but the original trilogy is leaps and bounds better than the prequels