Gotham Knight hands down; I personally preferred Studio 4C's "Have I got A Story For You" and Madhouse's "Deadshot" and "In Darkness Dwells".
I haven't seen Halo Legends completely yet despite uploaded two of the current versions on BBT.

But I'm not hating the ones I have seen. The Package was very entertaining.
Like DaggerLite I haven't really grasped a liking for the Matrix universe so most of the stories didn't really interest me much. Other than the ones who managed to impress in terms of animation and pacing.
I would say Gotham Knight. Most of them are right up my ally. That's just my opinion. It probably has something to do with me generally not having an interest for the two other franchises.
My friend hates Batman and actually hated Gotham Knight, big surprise. Apparently, he thinks he's boring because he doesn't have any special powers, but that's what makes him so interesting. He doesn't need any.