Hey Michael,
If you do a search on this forum for "Nearly Naked Notion" you'll find examples of recordings made from Notion "out of the box" with the standard sound sets. These will give you a good feeling for the kind of quality that's possible using Notion as a standalone music production tool. In my (admittedly biased) view, Notion is hands down the best
performing notation program out there.
Here's a recent scorecast video I put together to show off how effective Notion is as a standalone production station (everything in this video is native Notion (sounds, playback, score, recording) with the exception of the tenor voice.
Here's a recording made from Notion directly, but using VST libraries (they're pretty easy to use to expand Notion's sound sets):
Both of the above videos (there are lots of others out there too) will give you an idea of how powerful Notion is
without ever touching a DAW.If you want to get a feeling for what Notion is capable of when used in conjunction with Presonus Studio One check these out:
As far as the expansion sound sets go, my experience is that the expansions are additional instruments if a particular score needs them (jazz brass, guitars, etc.) My experience is that the basic sound set is more than enough to get you started. One plus with Notion is that the expansion sound sets are pretty inexpensive compared to some of the high-end VST libraries out there, and you can buy them as you need them.
As far as improvements over Notion 5, there are lots of functional improvements in the program. The sound sets haven't changed, so you won't notice any difference there.
Hope this helps!
Michael