It's really just a menu update
While Microsoft calls the new update an "entirely new experience," it's really just a streamlined menu system with a better online store and the addition of streaming movies. Depending on what games you play, your "Xbox Experience," so to speak, will not change much. But the menu is an improvement, and long-time 360 owners can still access the "Blade" menu by pressing the guide button at any time, in-game even.
It will help you discover new games
My favorite feature of the update is the revamped "Game Marketplace," which organizes all Xbox games -- including retail, Arcade titles, and Xbox Originals -- by box art and lets players sort by alphabetical order, new arrivals, genre, and a new "most popular" category. That last one is a great new way to see what others are playing, as well as find new games you may have missed. What's more, games have their own dedicated "detail pages" now, which include screenshots, descriptions, and all add-on content in a single location.
Streaming Netflix rentals are near perfect