i've owned a citizen tokyo. its not a good bike at all. in fact, i think for a person who hasnt been on a bike in a long time, owning a citizen bike could be a very discouraging experience. a 16" wheel bike would be better for train and bus commuting and are just about as fast as your legs are strong. if you dont need to get on the subway often, then a 20" bike might be better. my advice would be to look at craigslist for good deals on good quality bikes. below are a few that i just noticed in a quick search. they are all about half what they would cost retail (although probably more expensive than what you had in mind, its worth a little more money to get a good quality bike thats enjoyable to ride.) i didnt see any 16" bike though. a dahon curve is a good one that frequently pops up on c-list.

downtube:

http://newyork.craigslist.org/mnh/bik/3776964339.html

dahon helios:

http://newyork.craigslist.org/mnh/bik/3776118661.html

swift:

http://newyork.craigslist.org/que/bik/3784642302.html