I believe for every traveling scenario there would always be 2 sides of the story. Even if one is on a sponsored company trip for work, I am sure one would always prefer to have some form of travel convenience/less hassles in order to make himself/herself more comfortable throughout the overseas trip. I have landed in HND/NRT Airport frequently many times for the last 2 yrs, and also had conversation exchanges on this same topic with my own circle of friends who loves to travel to Japan. Most of us came down to one single consensus, Haneda Airport is definitely more convenient to get to/back forth via Downtown Tokyo area.
Threadstarter, if you are still quite new to Tokyo transport access, would suggest you to read up the following below, the map directions are pretty easy to understand for Keisei Electric Railway access and Tokyo Monorail access via Haneda International Airport terminal. And even if you are not intending to take the public transport like trains back to Haneda International on your departure flight day back to SG, riding a taxi would only cost you less than 6400 JPY from central downtown areas like Shibuya/Shinjuku. Been there done that before, and that's like what only ard 2400 JPY more only compared to that N'EX round trip ticket fare?
Tokyo Monorail Access to Downtown Tokyo
Keikyu Railway Train Line map (please only take the
Airport Limited Express, not the other express trains as it cuts down travel time significantly as it typically only takes
11 minutes to arrive at Shinagawa station. You can then make a transfer to JR Yamamoto line for the usual downtown areas located throughout Tokyo)
JR East Platform Guide (for ease of understanding on how to switch to JR Yamanote lines or Ueno Tokyo Line Limited Express, shd u choose to stay in Ueno as what other fellow forumers had prev suggested)
JR Shinagawa station is always a preferred alighting stop for regular travellers for switching to Yamanote line who often rides the Shinkansen express as often as me. Just ask those who travel frequently in Japan utilising the Tokaido Shinkansens coming back from well-populated kansai areas like Osaka/Kyoto or even Chubu regions like Nagoya, most who travel back to Tokyo for their remaining Tokyo leg itineraries would usually and likely make their stop at Shinagawa station, before doing local train transfers to their preferred destinations in downtown Tokyo areas.
Since Haneda International Airport terminal makes a direct transfer to Shinagawa station in abt 11 minutes, it is definitely a very convenient way of accessing to well-known Tokyo hotspots in a very short time. Even though N'EX Narita Express is a form of Shinkansen ride as well and also considered very pleasant and hassle-free way of getting back/forth to Tokyo or Narita Airport within 53mins to an hour, this transport method usually takes slightly more than 1hr (yes I have experienced 5-8 min train delays before while riding on the Narita Express back to the airport, so do my friends) so it is not exactly the most time efficient way of traveling if you ask me. In Narita Airport there is also another way of reaching Downtown Tokyo areas such as taking the Keisei Electric Skyliner option, but as I am not quite familiar with taking the Keisei Skyliner as I only rode on it once, so I shall not comment too much on their services/efficiency.
Cheers.
