I want to chime in here and back up Jimmys post. This is not to support any negativity that spreads through the internet on various channels, but rather from a guy who had (and still has) high hopes for VSL to once again lead the market with the best orchestral libraries out there!
But at this point, the Synchron Strings are far from that, I am afraid! I have several thoughts on that and I do not want to prematurely decide on any of them, because it takes a certain time to play and refelect and I only installed the library yesterday and played for an hour. Here only my most obvious observations.
While there is something to like about the short notes, it seems to me for the sake of playability the sample starts have been cut to early. I surely like to have a short patch as playable as Synchron, but when it comes at the price of getting unrealistic results, I would prefer a less playable one (or rather an option to switch between playable and good sounding, like other libraries offer without the need of loading an entirely new set of samples into ram). I might be wrong about this, but I believe this is also the main reson, why the shorts don't sound convincing to me in the higher dynamics. There is something there which suddenly makes you freeze, when you hit a velocity in the higher range and I am not talking about the fact that those are "harsh"! No, they just sound as not part of the performance. Clearly I know, that those harsh shorts cannot be played in rapid succession by string players, but even if you just hit one chord or note it sounds strange in a way I still cannot put my finger on it, why ... my best guess is, it is the editing. Further, I generally find those shorts a little to generic in their approach. There is only those super shorts and normal short and to be totally honest, I cannot hear much difference between those. They rather appear to me like time streched versions of the same (not saying, they are!) and it feels a little bit like waste of recources. I would much prefer a more string technique-oriented approach to shorts, like having a real spiccato (not going over the top with the dynamics) and a noticibly longer and meatier staccato (going all the way up there) and possibly other options (not necessary for a volume 1!). To sum up the shorts, I like them in the low dynmics quite a lot, but they need to become less exact, more human in some way. Otherwise, I can see not much use for them on their own (without layering with other samples) and this should reall be the case with a recource hungry library like this!
Regarding sutains, I lke the playable fp and sfz longs very much, as those are very useful and its great to have them like this with a sustained note after it! The normal sustains though seem a bit lifeless to me and in combination with all the legato techniques I just don't get a singing tone like in other libraries, although the competition just has 3 velocity layers most of the time. This IMO is a shame. I find one or two extra dynamic layers are justified by these sustains having more depth for very quiet stuff. I can see that Synchron is probably the best library out there for very intimate, ppp - p moments. But to my taste there is nothing to connect in between the layers. Crossfading them by CC does give some kind expressivity, but it always sounds held back to me and is far from a singing tone, which is what people arguably need most of the time when playingstring legato passages. I think you should have observed the competition more in that regard, as their have quite some improvements been made in the last decade. Certainly, I acknowledge, there are also drawbacks resulting from those techniques, mostly noticable in less playability and I appreciate the fact that VSL is trying to offer an entirely playble package here. But to me, a library of that size is just not justifiable if it focuses so much on that playabiity aspect over providing useful, less generic patches that represent the most needed (for Volume 1) string techniques to reproduce realistic sounding results.
The same goes for the legato techniques. I have to test them more throughly for sure and I find them better then a lot of people do for the most part, actually! But they are also a bit generic, seemingly crafted to provide some variations of a very playable patch. While I appreciate that to a certain degree, I keep wondering what to use these for ... so many times a patch sounds not bad, is very responsive under the fingers, but at the same time just doesn't sound like anything I would expect from a string orchestra. So, my whish for the legatos would be to keep some of that playability, but expand and improve a lot in realism, even if that means sacrificing the playabilty at times.
Altogether, I still hope the synchron series can be turned into a major success and the potential is there! But I believe, some of the core VSL philosophy has to be rethought to a certain degree. There is not so much use in the playbility aspect, if the musical expressiv result is often so much shallower then with the competition. I like the fact, that you guys tried to go over the top with e.g. velocity layers, but I am afraid I have to say there currently is not enough there to justify taxing your computer memory to this degree! There is positive, like the quiet stuff you can get out of these strings, but over all I have to say, this library falls short in just to many aspects, given its price (RSP) and first and foremost recource hunger. i hope you are listening and I whish you the best for 2018.