It’s not bad for the money.
It does have a large pallet of instruments, but keep in mind they have a mellow ‘concert/marching band’ tonality about them…not so good for brassy jazz or rock, nor the huge Waggner Orchestra sound. To get those you’d also want the Orchestra and Jazz libraries. The library was designed more or less to compose school music. It’s OK for that, with some WORK (learning to set the sound stage, and get the expressive data entered if/when Dorico guesses wrong).
In my opinion, they don’t sound very realistic in Dorico without a lot of extra work in the score, but it can be ok for a basic sketch-up. It can sound pretty darn good, but there is a learning curve to get there! Supplementing its weaker areas with other things that come with Dorico, plus whatever else you might have in terms of sound libraries can really fill it out into a quite useful library! Again…there is a significant learning curve to make it happen in something like Dorico.
Good brass tracks are hard to get out of loudspeakers period (even with real brass instruments), even harder from a VST, and really difficult to get out of a score interpreter. It’s a little bit more manageable from a tracking DAW if you’re good with mixing, compressors, and have a nice slate of EQ and reverb plugins. Some tricks that can really help include using mics in a good room to record the VST tracks as they play through the speakers. I know, it sounds crazy, but it really can work wonders on making digital brass sound more like the real deal. Problem there is…do you want to compose, or play sound engineer?
Having said all that, if you want something that’s pretty much plug and play in Dorico, Note Performer might be the better buy.
Garritan can sound pretty good, but it takes WORK to make it realistic and expressive. One will need to audition all the sounds pretty carefully and understand the strengths and weaknesses of each patch, how they best blend, how to get the expressive data into a score, and in some cases even go in and tweak the SFZ files of the instrument itself to fix some things. It has potential to get a nice sound stage using the built in effects, but it’ll take some practice, and the way the effect matrix is designed isn’t ideal for intuitively taking advantage of it from within Dorico.
NP will still sound like a band in a box, but it’s pretty much ready to roll with Dorico out of the box. It’s not too hard to roll off the harsh overtones while you’re sitting there composing (don’t shred your ears until you get ready for the final mixing stages), and add them back with a different set of effects when it comes time to do a rendered mix-down. It doesn’t have quite as many brass and woodwind instruments in the pallet set, but suitable substitutes are there for doing a nice mock-up, and it will have a lot of other things that don’t come with that Garritan C&B set (Like a full General MIDI pallet, and then some).
If I had to choose just one, and all I had to use it with were Dorico…I’d personally go for NP.
I’m glad I get to use both though. I do use Garritan Libraries quite a bit, but they are heavily supplemented (I have the full Garritan Ultimate collection…and loads of other non Garritan plugins), and I do most of the sound shaping in Cubase.
Other libraries worth mention…
HALion Symphonic Orchestra, as comes with Dorico Pro. Again, it takes WORK, but it’s pretty good for the big Waggner orchestra sound. There are a lot of weak areas in the library, but as a supplemental thing, in combination with NP or Garritan C&B, it can be pretty useful.
More modern high end stuff is out there as well. I’m not sure that I’d advise investing in them right away though. Unless some of them are shipped with expression maps and stuff for Dorcio…they can have quite a learning curve with Dorico as well. Plus, they’re going to be quite a bit more expensive than the stuff mentioned so far!