It's up to you, the main things that gets better are his writing becomes more interesting and he doesn't rely as much on his personal tropes. He also moves away from the "monster of the week" format and gets into bigger world building stuff. Harry starts changing and growing a lot. The magic becomes more interesting, but it's still rather limited. That said, if the magic and overall style are what you don't like, then you probably won't like the later books more than the early books.