Immortal Sun is a very strange but also a very sweet card. It has plenty of unrelated abilities, but they're all pretty good. Many decks will want to have it either in sideboard or 1-2 copies in the main deck just for the anti-planeswalkers effect. But other abilities are usable, too.
It won't spike in price, as it is quite an unusual card, but that is exactly why it will have its appeal in certain circles of the Magic community.