I am a GPO user, but I picked up a copy of GOS Lite a few years ago when Gary was running some kind of closeout/GPO user discount promotion.
I have basically never used it because I stopped using Gigastudio (I only had the GS32 and I was never happy with it).
I'm considering picking up a copy of K2 and wondered if it would be worthwhile to dust off my GOS Lite CDs and try to run them in Kontakt? Are they worth using or has GPO surpassed them? Do all the articulations/etc. translate well to the latest K2?
I have to admit, I've not tried this yet with Kontakt 2 - I've only just updated from version 1! Using that, I was able to translate the individual instrument articulations with few problems. What it didn't like was the multis. I don't know if this has been fixed in version 2, although I believe the giga import facility has been improved.
I'm currently working on an orchestration where I am planning to try and mix the samples in GOSL with GPO - the more libraries the better, or so I have been led to believe from reading these forums!
I did manage to produce some pretty good results from GOSL when I used giga, and as I said, you can certainly import the individual articulations to Kontakt, and presumably build up a multi there.
Give it a go I guess - you can always mix and match, and use different amounts of sound from the different libraries to produce the sound you are looking for.