Either camera is a massive step up from the D200. Id say if you can find an almost new D3s for 2K less than a new D4 than do that. If your looking at used bodies and not really saving much over a new D4 than your foolish for giving up the warranty over saving a little scratch.
Also if your ever plan on doing video than the D3s isn't for you, I was considering buying a D3s but ended up springing for the D4. Having a recording studio and a small record label I thought it would be a good idea to have the option to do video if I needed too.