One of the more common techniques for string libraries to get better sounds is to double two libraries together. While GPO and GIO can be made to sound good, they sometimes are weak in some areas as most libraries are.
Well, I found that Embertone has released Intimate String LITE for free (for those with Kontakt full version). They are pretty nice when mixed together and have legato versions as well as polyphonic versions. Here is a short test I did to show how string library doubling improves the sound overall.
Listen to the songs in order (01 - 04 ) and you can hear the progression of the sound with a final cue of all the instruments together.
Full Instrument List:
GIO - Full Strings Lush Sordino
GIO - Pizz Loose Full Strings
GIO - Timpani 2 and Rolls
GIO - Orch Perc Set 1
GPO - Violins 1 Lush
Embertone - Chapman Trumpet
PocketBlaus - Solo Cello
Embertone - Intimate Strings LITE Legato
Embertone - Intimate Strings LITE Poly Sustain
Embertone - Intimate Strings LITE Poly Sordino
Kontakt VSL - Viola Ensemble (for some warmth in the string section)
There are many paths to get the Kontakt Library for $200 or so. You have to wait for a sale or a cross-grade upgrade. For example, if you have JABB2 with the Kontakt Player, you can get this for $200 - $250.