This show pretty much was a part of my childhood and I think it's what actually introduced me properly to the Batman character. I might have seen a bit of Justice League before that, though couldn't understand english, but I digress.
Either way, I really like the aesthetic this show had. (The same studio did another of my favorite cartoons, Jackie Chan Adventures) The character designs were very stylized and in many cases improved from their older versions. This included Mr. Freeze, though he was now a mere thug with a cryogenic accident, and Bane who I might unjustifyingly love, because this version was the first I ever saw. Clayface also looked great and was actually a pretty tragic character.
What actually sold me the most was Joker's design. It was very different from the original, but suited the character with a more mutated look, wild hair and red eyes. The insanity was more blunt than calculating, and dear God I loved his voice. Kevin Michael Richardson did a really good job as his voice, going from the lowest growls to the highest pitches in perfect harmony.
I liked the show for the first three seasons, but arguably seasons 4 and 5 can be passed on. They're watchable, but I didn't really like the justice league thing they had going and I got really tired of the sidekicks. I liked the first two seasons when Batman worked solo, it was dark and gritty (including the intro), and honestly I didn't need anything else. The inclusion of Batgirl and later Robin was kinda meh, because they were a blatant attempt to appeal to a younger audience. The intros also turned more hyper, which was a turn off for me. And I was 10-11 back then, so the appeal effort went down the drain.