Simply put, it is one of, if not the, best fighting games ever.
If you haven't played Tekken before, it is a great fighting gaem that features many characters all with their own fighting style. It is one of the original fighting series, and I think it might be the oldest one still going and making sequels (I'm not sure though).
The reason it is so great is because of the great gameplay, the story, the characters, and the graphics. Tekken 3 had some of the best graphics done on Playstation (one).
Now this game specifically; the reason I think this game is better than all other Tekken games is because of the tag-team mode. It is the only Tekken where you can pick two characters and switch back and forth throughout the match (when one character is in play the other characters health slowly regenerates). This game had no story like the other Tekken games, but in this case it wasn't a bad thing. It gave you a break from concentrating on the story and just let you kick some ass. Also, without a specific story line, Namco was able to put any character they wanted (all characters from previous Tekkens + random characters that they could because of the game having no story).
If you are no to Tekken, or fighting games in general, I suggest you try this game.