Absolutely not true. The only sequel to FFVII is the film, Advent Children. FFX is nothing at all like FFVII.

As for the game, I'd say its enjoyable to any Final Fantasy fan really, but here are the main points so decide for yourself:

Graphics/Sound: If you like pretty pictures, FFX is gorgeous. You'll be completely wowed by its realism, and its haunting music. That, and the characters talk, which I find pretty cool, especially after turning off the subtitles.

Storyline: FFX has an interesting storyline, and it attempts to flesh out its minor characters as well as its major ones. Plus, it takes a good dig at organized religion.

Linearity: Unlike the previous FF games, X is VERY LINEAR. Meaning, you don't have a lot of freedom to decide where you go and when. The game forces you to go along with the storyline for almost the entire length of the game; you can't travel around the world map freely until right before begining the final sequence of events. To compare it to othe PSX FFs, it would be like getting mobility at the beginning of the last disc. For people who like to do their own thing, this sucks.

Battle System: It's pretty simple to grasp and the sphere grid is easy to use. However, learning abilities on the grid is again pretty linear for awhile until you collect rarer spheres which allow you to customize your characters more. You can also switch characters in and out of battle, which I think is useful in that it avoids the frustration of forgetting to put a magic user in the party before a fight against a creature who needs magic to defeat it. However, many find that this makes the game too easy because you have all your characters available for every fight, even random encounters. Finally, you can control summoned creatures in battle, which I think is cool, but again, makes the game easier to beat.

Overall: On the whole it's a pretty easy game compared to other FFs and is played through very quickly - this is good for some and bad for others. Personally I'd at least give it a shot, love it or hate it, but maybe now you can make a more informed decision.