Long time user of both platforms. Still own both (HD2 and Nuendo 3 with 3 firefaces, 3 uad, 3 poco.)
I prefer working in N deeply. There are a few functionalities I miss from PT, but no deal-breakers. The key thing is that, overall, I get more done faster in a day in N, and I'm less drained. It took me a while to get to that place- I started with PT, had used it for about 5 years before N, and kept trying to use N like PT. But once I understood the N approach, it was much easier.
The big difference is that N focuses on the object and the mouse, rather than tools and keystrokes, so you're not constantly converting the action you want to perform with one hand into a choice and action being performed by the other. You just don't have to jockey things around or think about how to get something done as much. If I want to change the size of something, I grab the edge of it and change it, rather that deciding I need a new tool, hitting a keystroke, and then changing it. Very subtle, but let me tell you, the cumulative value of hitting 5 fewer keystrokes in every minute is very powerful.
In addition, the objects are much more dynamic (fades don't have to be removed to trim a region, crossfades can stay in place while each side is trimmed back and forth, audio can be moved inside a region definition while fades remain in place...) It's a lot of little things, but it adds up to an easier day.
I still work a lot in PT outside of my place, but I don't if I can avoid it.
As for the sound, I'm fine with both now that it's HD, though the pan-law in PT bugs me a lot.