I played through Xenosaga I and really enjoyed it. Luckily, I timed that playthrough so I finished up several days before the release of Xenosaga II.
And Xenosaga II, although in the beginning it seems like a pretty fine game, turns out to be pretty bad. I played through and finished up around the 29 hour mark, because I did some of the unrequired GS side-quests, but the last 10 or so hours was a real push for me to finish up. The combat seemed pretty fun and fresh for me in the beginning. But it ended up just being pretty "bleh" and "unfun" for me towards the end.
It progresses the story of the first, which is a good thing because I really like the story, but as a stand-alone RPG it's pretty bad.
And what the heck! Don't take any breaks from SH:C! Now THAT'S a good game