I've been riding NS boards for several years, most recently a NS SL for the last 3. I have an older NS Premier (prior to the T1 designations and R&C technology).
NS SL - I love this board. It has been my go anywhere, do anything board for the last 3 years. I've mostly ridden it in the midwest where snow conditions can be anything from natural snow to man made, ice to granual, and almost anything else you can imagine. I've also taken this board out west a few years in a row to Breckenridge where I've gotten into real powder, trees, and of course groomers from green to double-black. I've also done a small amount of jumps and park with this board. It is stiff enough to really go fast and carve up a run and still hit boxes and rails in the park.
NS Premier (Non-T1, Non R&C) - As I mentioned, my only experience with the Premier is an older model I rode for a few years. I believe it is a 168 or maybe 174 so it is a big, long, stiff ROCKET on the snow. Definitely incredibly stable at speed and a carving beast. I've never done jumps with mine, the length is really not something you want to take airborne. To me, this board was all about going fast and being able to crush anything in my path. I also love this board but at the size and for the flex profile, for me it is really just a niche board and not an all-mountain freestyle. With a newer version of the Premier and in a shorter size this probably would not apply.
Either way, a NS board is a great choice!