Final Fantasy X is one of the best RPGs of all-time.
The combat in FFX takes a step away from the traditional Active Time Battle system that the series is known for in favor of the Conditional Time Battle system. In my opinion, I think it is better. Instead of a meter filling up over time in order to attack an enemy, you see portraits of the combatants in the upper right hand corner in a certain order depending on their speed attribute. Also, Final Fantasy X gives you the option to switch characters in your party during battle. So for an example, say you want all seven party members to gain experience in a battle. You can sub each one in, do one one attack then sub them out as much as you want. It is a good addition to the standard formula.
The leveling in FFX can be intimidating at first but you get used to it. Leveling up is taken care of by the Sphere Grid. The Sphere Grid is one giant grid that your characters level up from by using certain spheres that you naturally get through battle and sometimes find. Each character starts at a different point on the grid but can go all of the way around, learning abilities that only certain characters could achieve from the beginning. It sounds confusing, but once you start using it, it's really easy.
Ah, the sound in Final Fantasy X. It's very good most of the time. The music is amazing and the sound effects are great. Sometimes the voice acting can be a bit spotty. Characters like Auron, Lulu, and Seymour are great. The worst example of the voice acting would be the conversation between Yuna and Tidus about lightening up and relaxing and they laugh. That almost physically hurt me to listen to.
Long games and Final Fantasy are synonymous with each other. If you go through the story without doing many of the sidequests, depending on how much you want to train, it could take about 60 hours to beat. If you do most of the sidequests and mini games and other things, it could last you a good 100 hours and beyond.
Final Fantasy X is an amazing role-playing game with an amazing plot (I liked it so much that I didn't even talk about it here in case of spoilers), awesome characters, and addictive gameplay. If you haven't played this game and you are a role-playing game fan, get it, play it, and experience the awesomeness that is Final Fantasy X.