Xenoblade really is better or at least equal to TLS in almost every aspect I can think of.
Neither game's story was amazing so they're probably about equal in that though TLS uses one specific story element an annoying amount for me.
Graphics are better technically for TLS but Xenoblade has more interesting art design, particularly in the geography while TLS sufers from a plethora of corridors in often unimpressive locales.
Xenoblade's value is far better than TLS, and I think the battle system works better too even though TLS actually has something new and somewhat inventive while Xenoblade is not nearly as revolutionary as some seem to think. TLS just has these boss fights that focus on a single mechanic that is overly difficult to pull off: a move where you run up a wall and then jump off it to attack the boss.
Xenoblade has a lot to do but a large portion of those subquests are pretty lame and only good for the rewards instead of the quest itself. TLS on the other hand has very little to do but it's interesting.
So yeah, I'd go with Xenoblade unless you have something specifically against MMO-like battle systems.
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