Everyone has their "pros and cons" for any product they have. For this discussion, I'm going to be skewed towards the positive, and focus solely on "what I love about" each of the VSTs I have. I figured this is a way to focus on appreciation for the instruments, versus making it about a comparison.
So here goes my Pollyanna Post, with one-liners for each! 🙂
Pianoteq
Steinway D (NY) - rustic, grainy and raw.
Steinway D (HB) - powerful mid-range.
Steinway B - high realism for a modeled Steinway.
Shigeru Kawai SK-EX - creamy mid and high registries.
Bösendorfer 280VC - woody cabinet, charming in the upper mids.
C. Bechstein DG - versatilty for classical and jazz.
Grotrian - one of the most regal-sounding instruments.
Ant. Petrof - old-world sound, transports me to musical eras.
Petrof Mistral - versatility on the softest and heaviest passages.
Steingraeber - a wide array of sound, concertesque.
Blüthner - passionate, warm, brings out the melancholy and wistful emotions.
K2 - strong kick, pierces through anything ensemble.
Native Instruments
Alicias Keys - quick foray into Yamaha's.
The Gentleman - sentimental, I imagine sipping on a Scotch while playing.
The Maverick - sentimental as well, imagine playing Benjamin Button music.
Noire - intimate. absolutely intimate (in the factory setting, prior to adjusting color).
The Grandeur - mellifluous, and capable of making tear-jerker tones.
Claire - Fazioli with PED's, great for composition w/o need for additional layers. maximally emotive.
Garritan CFX Concert Grand
Epitomizes the "VST that emulates the sound of a concert setting" the most to me.
Vienna Symphonic Library (VSL)
Bösendorfer Imperial - luscious, nostalgic, grand-grand, ostensive mid-upper range.
Yamaha CFX - warmly voiced beast.
Fazioli F308 - smooth hammers. provides a flattering sound to players of all levels.
Steinway D-274 - most beautiful sounding Steinway that bucks my general perception of the maker.
Bösendorfer 280VC - in-your-face presence, low registries trance-like, combined with crystalline upper range.
Fazioli F212 - ethereal. sounds almost like an instrument that is "better than a piano."
Blüthner - authentic. beautiful, unfettered depiction of a bygone, and much-missed era.
Bösendorfer Upright - a very fun upright instrument that sings in a controlled manner.
German 1904 Upright - a gentleman. a charmer in all the registries and quickly makes one smile.
VI Labs Modern D
Playability/dynamic range makes multi-hour sessions a sheer delight.
I hope you enjoyed my descriptions above. They were written spontaneously, in the moment (similar to how I play the piano). I strongly believe that the capabilities, and wide variety of VSTs today is phenomenal, and it's easy to overlook how spoiled we are today, versus the olden days when the digital piano/VST offerings were atrocious in comparison.
Happy playing!