I just bought an X-150D and it is definitely Nitro. I has a few few of the same finish cracks that my 62 J-45 has, and you can see that the finish is very thin. I played the A-150 at a local music store and really liked it unplugged. I wasn't hot on the sound of it through the Marshal Slash amp they had at the shop though. I was also a bit hesitant about the pol finish on the Newark St. models.
I tend to keep guitars forever, and I love the way a good nitro finish ages. It isn't really logical, but I really prefer lacquer finished instruments.
My father has a Westerly d-52 acoustic, and it is the absolute best acoustic I've ever played. He had a Martin 28, but we sold it because nobody ever reached for it next to the Guild. The A-150 payed beautifully, and the tone was superb unplugged; even with the foam under the bridge. But the X-150 has something that the poly Korean guitar didn't. It has that next-level feel to it. Like my Dad's 52. Maybe it's perception, but perception is reality.