To the OP, you made the right choice with the Pen! Definitely the place to stay especially with a 10 and 80 yo. It is within easy walking distance to Ginza (and you can do so underground without crossing the streets) with all the eating and shopping you will ever need. The Ritz is a good as well since it is right on top of Midtown but a nice big shopping mall simply doesn't compare with Ginza.

jtrader is exactly right. Been going to Tokyo quite frequently and the GH is more expensive than the Ritz. I would take the Ritz any time over the GH since the GH rooms have seen its share of wear and tear, Ritz has better pool and also more centrally located. With the price difference, makes it a no brainer for me to stay at the Ritz.

The Seiyo Ginza was nice and would have been my first choice if I wanted to be in the Ginza area. But it is so dated now and offer minimal facilities. The Pen would be my choice these days in the Ginza area.