Xenogears was basically the Star Wars ANH of the Xeno games, except they never got to make Episodes 5 and 6. Like ANH, I'd also consider it the best, but that might be my bias since I grew up with it and only played half of Xenosaga 1--the TPM of the Xeno games.
If you like the idea of turn-based kung-fu combos and switching between fighting in a gaint mechsuit during battle, then I highly recommend it. The story is kind of like Evangelion Lite meets G Gundam played straight. At one point, you get to fight in your Gear in a 3D brawler arena, which is pretty dope and a nice break from the traditional RPG gameplay. If you're okay with grinding each character now and then, the game rewards you with a plethora of new magic kung-fu combos you can use later on in the game, with one of your characters' moveset being replaced by one that utilizes a sword. The game progression is pretty cool throughout, as there's always something interesting happening and big towns to explore with at least one Square easter egg in the first town. The music I'd rate slightly below that of Chrono Cross, but a big part of what makes this game exciting and memorable, with
one boss theme in particular making me think of Gundam Wing.
I'd rate Xenogears a Playstation JRPG classic and a must-play, but unfortunately they dropped the ball with Disc 2 due to time/budget constraints. They cut out a lot of the in-betweens for key events with just a main character sitting in a chair in front of a 70 inch TV and a text recap of what happened up to that point.