IX is a good game, but it's not without its flaws - the big one being it focuses so heavily on 3 of the main protagonists the rest get little to no time to truly shine as characters. It also has a massive number of time-sensitive sidequests, so if you wanna complete it 100%... (Well, that's virtually impossible, on account of Excalibur II and all.)

According to Sakaguchi himself it's everything he envisioned a Final Fantasy game to be, but just know what you're getting into before starting it up.