The ability to sacrifice it to tutor any other land in a player's deck is certainly powerful, though an effective 4 mana (3 + tapping Urza's Cave) to activate is a steep cost in a format as potentially fast as Modern
Just keep in mind that while in theory, foil mythics and rares add to the expected value of the set, your odds of actually opening a valuable foil in any specific box is pretty low, since they are quite rare
Prices are brutal for 151
Vivien Reid shines in grindy matchups, where she can remove key threats like Unholy Annex, Archfiend of the Dross, Overlord of the Hauntwoods, Deep-Cavern Bat, and Caretaker's Talent while leaving behind a formidable planeswalker
Luckily, there are places to take your cards in person and have them graded locally with an even quicker turnaround time