I think that my subtle experiences with VSL can be useful to you – maybe.
I´m not professional composer or musician. During the last year I was using EWQLSO (Platinum) with somehow contradictive results (because of my poor knowledge – now I understand it!), I liked this library in general and sometimes continue using it - with more pleasure now because understand it better.
I bought VSL SE Complete Bundle. This is a huge and really good sounding library. I didn´t like it first - for very dry sound, VI has its own reverb but if you add MIRx with VI Pro (or MIR pro - I don´t have it) the sound is more correct (realistic) – so adding those finally I obtained the sound I needed.
I don´t know why, but it works better with VE Pro 5 than directly in DAW, as well as Kontakt libraries (Ultimate 8) and Play 3 work better with it (I use mainly Pro Tools 10 on Mac Book Pro retina 2.7, RAM 16 G –probably because of 32-bit architecture of this DAW and VE Pro offers access to 64-bit and all of the RAM)
After buying and downloading VSL Dimension Strings - 2 days ago - and playing with it I can say that its sounds are yet more pleasant and realistic, but it requires more and more learning of possibilities of these libraries (that are endless, I think). So really wonderful sound! Now I can´t sleep at all - because of trying these sounds that are endless.
By the other hand VSL SE templates in VI Pro (all strings and others) are really extraordinary well made (I miss these templates for DS and hope that very soon we´ll have them for all DS – the work for very high estimated maestro Dietz and his team). And you can do everything with these templates and somehow modify them at your manner - and really don´t need other libraries - for weeks, months (or years).
So learning the software, making your own orchestra templates and listening to every sound of orchestra is the way to go – initially too slow (comparing to the other orchestra libraries) - but finally the sound is much better.
Because of having some experience with other libraries and VSL tutorials, using of VSL SE was relatively easy, but Great Tutorials (!) of Beat Kaufmann helped me to use better VSL SE, VI and VI Pro (first steps obviously – I´m a beginner yet), locate correctly the instruments and apply reverb - and learn the “constructive” listening to all the details of each sound and finally the music piece. The ancienty of achieving the good sound now is changed to constructive approach – what steps I must do to have that particular sound. And to use Cubase that I didn´t like at first but now use it more and more. (Changing the DAW helps to understand better the main principles of overall making digital sound I think).
But the way is really slow (for me) - mainly because of untrained ears (I´m a amateur so can´t dedicate too much time to music), so you have to be more patient to achieve the best results - and listen, listen, listen (“constructively” - what I´d do with this sound, what articulation should be better for that one etc)...
And buying the other new library or software after studying well that you just possess - because the possibilities of these packages are great.
So my experience is this:
VSL SE is great (complete bundle is very recommended), VSL VE Pro 5 is very useful, VSL VI Pro 2 (and MIRx) is highly recommended, VSL DS is wonderful.
I hope that was helpful.