JSRF is, by all and any means, the best game of its genre.
You're set in a world where emotions are outlawed - the police make sure of it. The protagonist you play is a hooligan from an inline skating gang that tags various parts of the city. It's a pretty profound idea, really. Y'know, being part of a hypothetical emotionless world. JSRF is one of those games that actually has meaning behind its story.
* Gameplay is fluid. One of the most, if not the most, fluid game I've ever played. I can't really describe it. All I can say is that the mechanics is very fast paced. The more tricks you do, the faster you go. Jumping off a grind, tagging a 20ft long wall and jumping to the other grind could happen in fractions of a second. If you're ever in trouble and can't jump something because "it's just too far," do some tricks and pickup speed :)
* Mechanics are easy to grasp. The controls have been dumbed down since JGR.
* The gameplay is, at times, not challenging at all. And no, it's not because of the simplified controls
* The music is just wonderful and fits the game perfectly. You're set in a world where emotions are pretty much outlawed. All of the music - well, all the songs except Birthday Cake - contribute to the game's appeal. It's very artistic, really. How they could create a game with really good, original music, I mean. (I even bought the soundtrack, it has been ten years and Aisle 10 is still part of my favorite songs. Yes, this is coming from the guy who listens to Maiden, Lennon, Metallica, Rolling Stones and John McLean)
The art in this game is just... groundbreaking. I plugged in my ol' dusty XBox 8 years later and I can still appreciate the graphics. I just really, really like the way this game looks. The reason I called this "art" and not "graphics" is because the game, itself, is art.
All in all, JSRF is an underappreciated game. If you have the money and the time, I suggest you buy this game. It is in my top 10 games of all time. Considering that 8 of my top 10s are RPGs with epic storylines, that has to mean something... right?