Unlike pretty much every other option out there, you're not limited to pre-determined articulations. You control all of the dynamics yourself, e.g. using an expression pedal or a breath controller (one of those is absolutely required unless you can get by with manually programming every single note and MIDI control - the instruments don't even output anything if you don't send CC11 expression data). Want a note to go back and forth between quiet and loud at precisely your pace? Easy!
None of this "keyswitch to marcato" nonsense. No limitation to 20 arbitrary articulations. You only use keyswitches for a few things: col legno, pizzicato, harmonics, higher playing positions, allowing open strings, bow change / detaché / tremolo (can be done purely via normal playing, too, these are just for convenience) and turning off legato in favour of arbitrary polyphony (realism be damned), and switching between different microtunings. Everything else is just notes and expression, and maybe finetuning with MIDI CC.
Speaking of, you can control all of this via MIDI in real time:
- Vibrato, legato/portamento
- Bow noises, overtones, impulse response of instrument body, early reflections (properly accounting for the instrument's position in virtual space)
- Ensemble size, synchronization of vibrato across ensemble
- Effect of bow pressure changes on pitch and dynamics
- Bow changes
- Individual harmonics of the notes
- Microtuning (switching between customizable presets)
The only downside is that the vibrato is easy to get to sound unnatural. However, if you know what you're doing, it sounds pretty damn amazing. Check out the demos at the link above.
Oh, and the price. €399 plus currency conversion and VAT.