Neopan 1600 is one of my personal favourite films - so much so that I now only shoot Neopan (100, 400, and 1600).
The 1600 has a wonderfully unique grain structure and tonal structure. As many people will tell you, you do have to be quite careful with agitation when developing it, as it is by nature very contrasty. If you're getting the film developed at a lab, try and find a lab that can accomodate special developing requests (ie, a lab that works with dip and dunk processing, and not automated machines).
It handles pushing to 3200 quite well; I've only pushed it to 6400 once, and the contrast was out of control - I had perhaps one or two zones between black and white! It also handles pulling quite well. Most people tend to expose it at 1000 - 1200 to extract a little more shadow detail. I've shot it as low as 400 with acceptable results, with better results at 800. Again, particularly watch the agitation/contrast when pulling it.
The grain structure is somewhat gritty, and while it works well enough for 'softer' subject matter, it excels at darker/grimier subjects - this tends to be more personal preference, though.
Enjoy shooting it! 🙂