Personally I love Phantom Hourglass. It's one of my top 5 favorite Zelda titles. Meanwhile, in contrast, I never even finished Spirit Tracks. I want to say it's because it was tedious, as a result of the train mechanic, but objectively the Temple of the Ocean King was way worse. I think Phantom Hourglass just had a more compelling stories and characters. Linebeck is an absolute icon and Ciela is one of the series best companions. While the Ocean king Temple was annoying, it was also challenging in a great way. I just couldn't find myself that interested in Spirit Tracks. I also can't say much for FSA since I haven't played it.