We all know that the legato transitions in strings are among the most important aspects of creating those beautiful lyrical melodies! 
So of all string libraries on the market that you heard, which do you have the most beautiful and also flexible (several variations) of legato?
Cinematic studio strings
Audio imperia nucleus
I currently use Afflatus Strings as my main strings, as I love the tone and the legatos. But I heard so much great things about the legatos in CSS.
Does Nucleus have adaptable legato (many legato timings)?
Css I own and like the most. There you can choose between classic, advanced and others depending on how hard you hit the keys.
Audio imperia I donāt own so I donāt know how adaptable it is but I think the sound is perfekt when Iāve heard it on livestreams.
On CSS, can you remove the āattack timeā so that it is easy to record live with MIDI keyboard? Iāve heard that it lags a lot due to having more āairā-time in the beginning of notes especially legatos. Not sure how to describe it but I hope you know what I mean? With Nucleus they had that feature to remove that initial āair/attackā-latency while recording, and then put it back afterwards for more realism.
Reason is I always record all parts in my music live with my MIDI keyboard.
Yes it has those features but sadly Iāve gotten use to compensate a bit while playing which doesnāt make it perfect and I correct afterwards. When playing live I like Cs2, 8dio anthology, Adagietto.
If talking sound I absolutely love albion one
Yes I still love CS2 as well, and it is excellent for recording parts live. But the tone and sound quality is not as good as the newer CSS.
Albion sounds amazing, but itās not what I want, because I write with individual instruments mostly. Not āStrings Low, Strings Highā.
All of these are great libraries, though just using orchestral libraries will diminish your results. I suggest mixing your orchestral library with a smaller chamber section or solo section subtly so that you add back in the definition that is lost from recording larger ensembles. This gives a richer more detailed result, especially when you use a library that has included intentional mistakes in the red or ding process for realism.
Christian Henderson describes his approach to sample library recording as ārecording the chaos with the beautyā. That way the realism is included in the sound. This is something Iām also including in my own sample library in a sorts and if really does help.
As Iāve spoken about Christian Henderson Iām naturally starting with two libraries from spitfire which I swear by. Studio strings and solo strings. Other manufacturers that do this approach well though include performance samples and 8dio. Though Iām finding that if you can include a live player thatās even better still. I recently started learning violin which really helps.
My goto strings are Spitfire Symphonic, Chamber, and Solo, but Iāve also used 8Dio Anthology and Intimate Studio Strings on occasions. Depends on what sound Iām going for.
Note in particular Spitfire Solo Strings: I usually use those as first chairs along with Symphonic or Chamber, to add more detail and control. Even just duplicating the ensemble tracks with automation and all for the first chairs can make a big difference.
The next step would obviously be to play the first chairs on actual instruments, which could probably do a lot to circumvents the limited articulations of sample libraries. Working on that, but I donāt have or play viola or double bass. Yet. 
David, becoming the one man string quartet.
Well, jokes aside this is the reason I am always looking for that next level of realism with software instruments that I can actually play and record with the best expression and articulation control as possible.
Controlling legato timing more naturally (from fast legato to full on portamento and even glissando), and vibrato (including both depth and speed) would be so amazing. Especially if there was also a way to add those extra articulations in the performance to really make it more dynamic and full of variation. Like different types of accented notes (marcato, sforzato etc.), slide-ins etc.
Spitfire symphonic and studio strings are highest on my wishlist but Iāve already spent way to much money on librariesšmaybe in the future.