bluemeansgo comments

The Maglev's platforms are going to be 40 meters underground, so tack on an extra 20 minutes beyond the Shink time to your journey time.

20 minutes? Come on. The deepest subway system in the world is 102m and it's a 4 minute escalator ride: https://www.youtube.com/watch?v=TWqNqm1GJbA Deep stations aren't a big deal for long-distance rail. They only really make a huge difference for subways and short trips.

And if your office happens to be in Shinagawa and your client's right outside Nagoya Station...great! Otherwise, like the vast majority of people, you'll need to factor in quite a bit more time. When I go to Shinagawa, my quickest approach is nearly always the Yamanote, an every stop line, and it takes quite a while.

Yes, it's too bad that they didn't run it into Shinjuku, which has the most connections in all of Tokyo, but in reality, it's all about land-use. JR Central has a much bigger stake at Shinagawa and none at Shinjuku which is pretty much built out and it will be able to build a proper South Tokyo hub around there. Watch that space 10 years from now. Chances are you'll see a lot of new development. It's also perfectly positioned for transfers from Haneda. If there's demand for it, I'm sure you'll see an extension to Tokyo Station. Who knows, maybe they'll repurpose the Shinkansen lines for Maglev and have Shink stop at Shinagawa. gasp

For instance, the Skyliner to Narita is 36 minutes. But my actual journey from fairly central Tokyo is about an hour and a half. When the new trains and improvements shaved the Skyliner's time, it made only a tiny difference to my total journey.

Yeah, the N'EX is still a better option for MOST people, especially if they're going to West Tokyo. If they ever push the SkyLiner more centrally it could be a viable alternative.

That does illustrate something very interesting, though. The trip from Narita to Tokyo is LONGER than Nagoya – Shinagawa. Nagoyans who live near the station could take a 40 min. Maglev to Shinagawa + 25 min. ride to Haneda rather than fly out of Nagoya's Central Japan Int'l ( 47 minute train ride ).

There will be almost NO reason to ever fly between those two airports, unless you're connecting to another flight. There will definitely be some real implications to the domestic air routes.