We talking the entire series, 1, X, or 2?
Regardless, yes, it is very worth it. It is one of the greatest JRPGs of all time and, as of 2, the series is now my favorite video game series of all time, dethroning the original king which was Fire Emblem.
Regarding 1 and 2, the stories are simply beautiful, always keeping you interested. Personal preference for me is that 2's story is better than 1, because, as good as 1's story is, there is filler in it and the characters have varying degrees of relevancy (but they're all still very likable). 2 doesn't have that issue, so not only did i like 2's story more, i liked it's characters more.
X's story isn't that good but the story was never the focus in X. Instead, it was the gameplay and characters. While i've never played it, i hear X has excellent gameplay and the characters have a lot of depth to them.
Each Xenoblade game easily gets you 100+ hours of content. While 1 and 2's stories can be finished within 80-90 hours, there's still a lot of content. X is the only one with an actual post-game (1 and 2 simply take you to right before the final boss) but there are plenty of things to do. From quests, taking on the Unique Monsters (Tyrants, as they are called in X) and superbosses (superbosses don't appear until the final chapter), to finding all of the Heart-to-Hearts (which are similar to Fire Emblem's Support Conversations), to simply exploring new places. X's world is the biggest, so it has the most exploration. The game rewards you for simply exploring by giving you gold, EXP, and other things upon reaching a Landmark. Landmarks serve as skip-travel points so backtracking is never an issue. If you die, you return to the last Landmark you visited. Speaking of, death doesn't punish you. You never lose anything by dying, which is very fair, considering it's possible to run into high-level monsters in early areas.
Combat-wise, the games are the same but different. I can't speak for X here as i've never played but 1 and 2 have great combat, with 2 being better at it. 1 is the more simpler, while 2 is the more complex. I'm sure you've seen the basics. Battles are real-time, with an emphasis on positioning. They can be a bit slow at first but once you start getting the hang of it, they become fun. The key difference between 1, X, and 2 is that in 2, you can't auto-attack while moving. This doesn't bother me at all, because 2's combat is way more strategic and deeper than 1's combat. 1's combat is still good though.
The music is God-tier. 2 has the best soundtrack of 2017, and i will fight anyone on that. Beyond that, Xenoblade Chronicles as a whole has the best music out of any Nintendo franchise. X does have the weakest soundtrack of the three games but it's still a great listen (though opinion on X as a whole is divided among the Xenoblade community)
My ratings
- Xenoblade Chronicles: 9/10
- Xenoblade Chronicles 2: 10/10 (it's also my GOTY 2017)