Thought I'd chime in with my experience:
Was initially overwhelmed by all of the different systems introduced (arts, Monado arts, gems, inventory, quests, collectibles, premonition battle events, team attacks, status effects, affinity, skill trees, etc.) having not having played a JRPG since the SNES, but after getting ruined by the tentacle boss on Bionis' Leg I spent three and a half hours going back, doing side quests, leveling up, and generally figuring out how the game actually worked (you can level up your specials! you're supposed to use your arts in battle non-stop, not just wait for one or two to refill!), and got completely hooked. I returned to the Mechanis tentacle boss and proceeded to wipe the floor with him, and anticipated forty more hours of a JRPG good time unmatched since the Final Fantasy 6/Chrono Trigger days. Then, right as the boss was on its last tentacles, the game froze and my Wii went to the black screen disc read error.
It now won't read any discs at all. I have a first gen Wii, which has been getting louder and louder over time, but it finally kicked the optical bucket. This is particularly troublesome, as I had no plans on playing any other retail games after Xenoblade. This was to be the swan song, and I now I'm in the position of paying to get it repaired to finish the game or just letting it die. $50 on Xenoblade lost (- resale potential - experience of playing game) or and addition $70+ to resurrect my senescent Wii long enough to finish it?