Favorite Answer:

That's subjective, and depends solely on an individuals taste. Not only that, but their knowledge/awareness of artists/composers within both genres. This will form their unique opinion. Therefore, everyone's definition of "better" will differ in this sense. Perhaps asking which they prefer would be more appropriate.

For me, I have thousands upon thousands of rock albums and ditto for classical.

As for rock and classical in general, I will say I enjoy both equally. However, post 2000 rock can be hit 'n miss for me. A lot of derivative nonsense that I tire of quickly. This has nothing to do with "sucking at finding good music", Lol. It's more a matter of taste, as I've heard loads of post-2000 rock music. Some of which others might enjoy very much.

So with regards to the post-2000 comparison, classical will tend to hold my interests more. That said, I still wouldn't use "better" to describe something that's apples vs oranges, subjective, and more personal opinion based.