User blog comment:Miskos3/Fairy Tail Chapter 320: Roaring Thunder, Review/@comment-6146666-20130301082337/@comment-2214433-20130301082827

Yes, Stay/Night was first but Zero is a prequel. So basically, the events of Zero happened before the Stay Night ones. Personally, I didn't like Stay Night as much as Zero, the animation isn't too good (well, the series is older so yeah), the fights are definitely not as good as in Zero and the characters are somewhat boring, compared to Zero again. So I suggest watching Zero without worrying about Stay Night.