I am considering a Rolex Datejust 1601.

Shortest I can add - if anyone is thinking of getting a 1601, it's not a bad choice at all. The first Swiss watch I bought for myself was a 1601. Still got it, still wear it in regular rotation and it led to a renewal of my interest in watches in general. They were and are extremely good. There's all the time in the world to pick out the right one, and many examples pop up regularly. Plus: the question is around 3 years old here, and the above still applies.