Well, I haven’t used NP4 with the newly supported libraries, but I can definitively say this, at least.
No single library is the best at everything. In what I do in a DAW, I mix and match, and layer, to get the sound I want. I use combinations of Spitfire, Orchestral Tools, and many, many other libraries to get the patch that sounds best at whatever I need it to, even if it’s for a single note (usually a really long held, evolving note of extended techniques, in such a case, but the point still stands). I don’t believe, even with NP4, that it can mix, match and layer multiple libraries together, on a note by note, phrase by phrase basis, can it?
Additionally, I frequently do things in the DAW to get the ideal sound that are not “technically” correct. I might use a French Horn sample and layer it with Trombones when technically it should just be Trombones, just because I like how it sounds with the sample. I might use staccatos on a lower velocity and crank the volume, because I like the texture it creates - and then later use the velocity maxed out and lower the volume to compensate! And I frequently EQ samples because they have resonances that muddy up the mix, and automate that EQ so that I’m only carving out those frequencies when they’re a problem, and not hollowing out the sound across the board.
A lot of my work uses extended and aleatoric techniques (for beautiful music as well as tense, horror stuff). How well does NP do any of that??
In short, how big of a delta is it between my work in my DAW and NP? Infinite. NP cannot do what I do in a DAW at all. And that includes traditional orchestral material.
But for someone who is just writing music which NP was designed for, and they aren’t trying to produce stuff at an exactingly high standard and just want it to sound pleasing for them, or passable enough to pitch to orchestras to get a piece programmed, NP is great. It’s a ton less work and sounds very reasonable. And it gets better with every version. But it will never replace my DAW, and it’s not meant to. They’re only competing against the people who begrudgingly approached a DAW because their Finale or Sibelius output was so god awful that they had no other choice. They’re not competing against DAWS as a whole for mockups.