I know this subject has been hashed to death, but it is a "competition" that seems to persist, and maybe we'll never understand why. Very different series, with very different audiences.
Did I enjoy both? Sure.
Would I read them both over again, indefinitely? Nope. I pooped out after a second read-through of the first three Twilight books (couldn't even convince myself to read Breaking Dawn again. No thanks!), but have read all of the HP books at least 5 or 6 times through.
Some people like pancakes for breakfast, some people like eggs. If I had to pick just one, I'd pick eggs, because they keep me satisfied longer.
But that's just personal preference.