I've always thought this to be one of my favorite US animated shows. I initially had some hesitance to watch it because, despite my love for martial arts films, I figured it was just a cash in on Jackie's name, and while it definitely was that, it seemed that some effort actually went into the show. The first episode really took me by surprise and made me an instant fan of the show, and I was surprisingly amused to know that the voice actor for Jackie's character wasn't actually Jackie himself.
The first episode was really interesting to me because I've always been a fan of shows that can pull off the whole MacGuffin theme in an interesting manner, and this show definitely had that for me. I loved the core cast of characters and a lot of the supporting characters were easy for me to be fans of as well. The villains were appealing in that there was a nice variation of comedic to straight up evil characters in their ranks.
In general, the first season was really fun to watch, the episodes that actually dealt with the season-long plot always had me hooked. The way the first season ended was really great, gave a nice amount of closure to a lot of the characters and their stories. The second season was rather...very bland to me, the actual mission was decent, but the insane amount of filler just killed my interest in it, though I loved its finale. The third season seemed like such a rehash of the first two seasons and there just wasn't anything that hooked me in too much.
I guess I'll be in the minority and say that season four was actually my favorite. I felt it gave the series a bit of a wider scope, things such as Tohru taking more of the spotlight against Uncle, and especially the J2 episode, felt like it was a sort of passing the torch season to the younger generation of warriors. Those things aside, I absolutely loved the Japanese mythology with the Oni masks, their designs were really appealing. I also loved the Shadowkahn tribes and thought that was one of the most unique aspects of the entire series itself.
I'll be honest and say I didn't see all of season five, though I've been trying to, but finding episodes and my general unenthusiastic attitude towards it are making it difficult to get through the season, though I have seen the finale and it was...decent. Certainly not the sort of thing I wanted for the end of such an interesting series, though I hear a lot of the original production staff left after the fourth season, so I suppose that drop in quality is understandable, though not acceptable in my eyes.