The topic of string libraries is always current and interesting: based on my experience, which has been growing over the years, I believe that before comparing various libraries and making certain choices, one should understand the philosophy of the producing company: what are they looking for—realism, epicness, or a middle ground to satisfy everyone? And then: do they want to provide a product that is ready "out of the box" (as is fashionable to say...) or a product with which to recreate positioning and environments? These choices are fundamental for deciding which direction to take.
Furthermore, keeping that premise in mind, there are products that are objectively superior to others; some libraries are now obsolete. Also, another very important thing: you cannot judge a library by how it sounds in Finale or Sibelius; good libraries are made for DAWs (Cubase and similar), because they must be PROGRAMMED based on articulations: the sample used for legato cannot be used for the first note of a phrase, because obviously it starts from nothing rather than from a connected note. Nowadays, simple articulations like legato, staccato, spiccato, pizzicato, tremolo, etc., are no longer enough; there needs to be control over the overall singability of every single phrase, a control that should reflect the real way of playing the instrument.
Currently, most of the development work on string libraries is focused on legato transitions and the agility of the legato itself, because good or decent samples regarding timbre can now be found almost everywhere; after that, it truly becomes a matter of taste. Regarding the aspect I mentioned before, Spitfire strings seem like excellent products to me—a British company that focuses heavily on realism; the samples are not necessarily full of reverb; you can mix the various microphone positions and make them drier.
8Dio is also developing strings that are very agile in legato, since the transitions in the Adagio series were truly too slow. Vienna remains a constant guarantee of quality, and the idea behind the Dimension series—combining smaller sections to form a larger one—is excellent, because each of the small sections has its own timbral characteristics and controls. This system was already present in LASS, which however falls short in vibrato and is overall somewhat dated.
Berlin Strings are also good, although quality decreases across the various string sections; that is, the Violins I are excellent, the Seconds a bit less, the Violas even less, the Cellos are almost crap, and the Double Basses are completely crap..... (it seems unbelievable but it's true; perhaps along the way they have increasingly patched things together...).
Then there is EastWest, which doesn't worry much about realism and prefers a ready-made product for Hollywood productions: it always makes quite an impression, but as usual, it depends on what you are looking for in a library.
I would say that currently these are the best brands; others are clearly inferior: Garritan is unbearable, the same goes for Kirk Hunter (for goodness' sake), LSS (not to be confused with LASS) is a product of a significantly lower level, Cinestrings and Cinematic Strings sit at an intermediate level between the top libraries and the others: Cinestrings is also usable for epic scenarios, while Cinematic Strings, in my opinion, is a somewhat underrated library; it is quite versatile and has a good timbre, especially in the lows, even if overall it is now a bit dated. And then, unbelievable as it may seem, Symphobia, despite being very old, still holds its own, especially if used as support to be doubled by more modern and versatile libraries; it provides a roundness and an overall blend that still works.
In short, one must absolutely not judge a library by how it sounds in standalone or, even worse, how it sounds in a notation program; it must be judged by how it sounds when it is programmed, assuming equal quality of the programmer.