The NX Base models are available at most Lexus dealerships. They came in a few days ago. Some are getting them at the end of the week. The F Sport trim (which I think is a huge upgrade over the base model in terms of looks) sounds like it may not be available until January 2016. I recently put in an order for an F Sport. Anxious for it to arrive.
The price is slightly less than an RX350, but you're still looking at somewhere in the mid-30s to low 50k as the range for the NX depending on the trim. IMO both vehicles target different buyers and personally, I don't like the look of the RX much.