SCS has quite a lot more articulations—SSS and SCS share most core articulations, but SCS has additional ones and more legato types. SCS is a much smaller ensemble and so both more detailed and more agile. But it's also not as smooth or as weighty (though SCS can be surprisingly weighty for its size—one of the peculiarities of sampling), and it has some intonational issues (evident because of the small size of the sections), which drive some crazy. Personally, I find because SCS has so many articulations and legatos, you can almost always find a quick workaround if you encounter something that is too much of an issue (and in context, I don't ordinarily find they are much of an issue unless you are repeatedly going to a bad sample in an exposed passage). Others complain about the tone of SCS, which is a bit nasally, but which I like. I always find SSS a bit ponderous but also lacking in bite compared to SCS. I usually start with SCS and add SSS for weight if I feel I need it. If you want the divisi effect, I find it works best if you layer SSS and SCS in tutti passages and then go to SCS for the divisi. That way I find it sounds less like you have changed orchestras... But here as with everything so much depends on the music you write, and what works for my music may not work for yours...
In terms of working with SCS and SSS, the differences come with things like getting the legato right, the transitions between dynamic layers, the agility of the samples, how consistent the timing of the samples is, how the vibrato sounds, the way the samples take automation, especially CC1, the release samples, etc. I find it takes me far less time to get SCS to where I want it than SSS. Often I never get SSS fully to where I'd like it to be, and so have increasingly started to use HZS instead.