I did not try these libraries but some others. There is a lot of good strings libraries but I have come to the conclusion that the best one is the one that you know the best. I think the major part of a good mockup is in the midi programming and performance.
Some really nice sounding libraries sometimes lack in the number of articulations. Or sometimes the legato patch are too slow or too fast for some passage. I found that VSL almost always have the good patch for every musical phrase, specially the Dimensions. Adding some Dim Strings to others libraries gives life and realism.
Spitfire in general are really nicelly recorded, but I never used it, exept for the solo strings that I bought (nice but limited). But this is a small library.
I know there's a new one, Berlin strings. Have check the demos, again, good but how is it to work with? If I could have a try on every libraries I could have a real opinion.