I have no experience with New York City other than what I've seen on TV. However, I have used my RNineT for commuting to work (mostly freeway) but some city along the way. I have about 18,000 miles of experience for commuting.
If it were me (and in a big city), I would look for a reliable small bike in the 200 to 300 cc range. My BMW G310R is perfect for this. It is a small bike and weighs about 300 lbs. It's very easy to maneuver in tight spaces and I can practically make a U-turn in a single parking space. I've had it up to 100 mph so it definitely has enough HP to get moving. It does not have the pickup that the 1200 has and I have to plan ahead if I need to pass someone and make sure I have plenty of room. I added a trunk to the back which is ugly but adds storage since there is none otherwise. The bikes are cheap as mine was $5700 brand new with all taxes & registration. Used ones are a bit cheaper. You definitely won't have that "classic" feel or image but you will have a bike that always runs and is an easy commuter. The brakes are good but not as good as my RNineT. For split lane-ing, it's really about the same as the RNineT as the handle bars are about 1 inch narrower; the bike itself is narrower.
ps. it sounds like an electric sewing machine until you rev it and then it becomes a beast.
