The N'EX does not simplify the process of getting into Tokyo. (The minute you get off the train and set foot in Tokyo Eki you'll see why.) The Friendly Limousine Bus, however, does. They have more frequent departures than the N'EX and will conveniently deposit you right in the driveway of your hotel. They even have English-language recordings to tell you what hotel you're at in case you're not paying attention to the scenery.

Now, as for getting from Tokyo back to the airport... This is where the N'EX can indeed make things more simple, especially if you don't want to leave directly from your hotel.

Be aware, too, that N'EX has reserved seating in both directions.