In my 'opinion', the default Finale setup for the new Orchestral Strings (particularly tutti string sections) take some practice and tweaking to make sound musical and on the proper beat.

The new Solo strings are quite nice I think, but again it takes some practice (just playing it with a keyboard, or with a tracking DAW) to get an idea of how to best play it.  Once it's better understood, Finale can be tweaked out to make it quite musical. 

Each piece will have different HP requirements depending on tempo, style, aggressiveness, and articulation demands.  Fortunately, Finale allows one to use the MIDI tool and 'embed' different sets of techniques into the score, so one can run multiple passes as needed to apply different sets of articulation choices (I.E.  Sometimes we want notes with a dot to be played staccato, other times we want it played martele, or spiccato, etc.)

The good news is that you can always use the score manager to revert to what I call the Legacy Strings (same as with GPO4, which is quite similar to the Finale Library but with more options).

I found what came across to me as conflicting HP techniques between the Finale, GPO4, and GPO5 libraries after installing GPO5.  One can simply go through an disable HP techniques he's not using to get rid of the wrong key-switches, or make the filters more strict.

To sort this out I went through and refined the filters to avoid conflicts.  One can grab a sample score with HP settings attached here:

https://makemusic.zendesk.com/hc/en-us/community/posts/115007755108-My-Finale-GPO-Soundset

It's not perfect, but it should avoid several of the conflicting key-switches between the Finale, GPO4, and GPO5 libraries while giving a good starting template.

As for the rest of GPO5, there is additional value in the new organs, harps, choirs, and pianos.