Thanks for your thoughts on this @JohnG . I'm going to listen to both SSS and SCS a bit more and see how I feel. Currently I don't own a string ensemble library at all (only violin and cello solo instruments) so this would be my first. The biggest thing holding me back right now as discussed earlier is my concern over the fact that all three of the libraries discussed (SSS, SCS, CSS) were recorded in position. I noticed yesterday that NI Symphony Series Strings was not recorded in position. I had already discounted it as an option a few days back because it seemed that it just wasn't as high quality as the other libraries mentioned in this thread. At this point though, given the fact that I know it won't introduce panning issues I'm starting to reconsider it. (It's also only $250 for Black Friday).Haven't used CSS yet (see previous post).
SSS and SCS -- trust your own ears and instincts. If one seems better to you, personally, don't be swayed by what I or anyone else says.
Nevertheless, a few thoughts, though they are very subjective:
1. SSS is a much bigger section -- much -- than SCS, and the sound is very different in consequence.
2. Both have a lot of unusual-but-useful articulations, including, for example, a "brush" short articulation that I haven't seen in other libraries. So, put another way, both are very useful and good quality.
3. If you are not hearing a big difference between SSS and SCS in the demos (not saying you aren't but just in case...) then get some better headphones or speakers to audition them. It's a very big difference in sound.
4. For what it's worth, people who have very good ears and are very good composers really rave about SCS; I like both but... (see next point below).
5. If you already own, say, Hollywood Strings from East West or any of the "big section" sample libraries, most likely SCS is going to be "more different" than what you own today. That doesn't mean you will be happier with SCS than SSS because it depends on what kind of material you like to write, but SSS is more able to convey the idea of lots of players and an overall bigger vibe than SCS, in my view.
But even that's only "sort of" true. You can always fiddle with reverb to throw a small section into a bigger space, or use the different mic positions to accomplish the same thing.
If you're torn between SSS and SCS, I recommend listening very carefully to Andy Blaney's dazzling demos and follow what your own ears tell you.
Also since the whole "in position" issues has become my focus I think I'll change the thread title and my original post to reflect that.
Thanks again for all your input.