This synth attempts and succeeds to break new ground in sound. To be honest I haven't heard anything that sounds exactly like it, it has a unique flavor to it.
But mostly, it is packaged as a String-modelling synth, and its shiny user-interface is based on the wood you see in violins and cellos. For those looking for a realistic Orchestral VST for their studio, I must warn you, this synth gets close but does not sound exactly like your standard bowed string instruments. However, the sounds it creates are unique, rich and believable at times, subdued or leading, and it is definitely worth opening up and trying it out. When you consider how complex it must be to try and model a bowed string sound using a program, you can see that a lot of hard work went into this, and the result is quality.
This synth has character of its own and makes bowed instruments sounds that don’t exist in real life yet are close to realistic and it will find a place in your projects if you let it.
Something about this instrument that might be a pro or a con depending on how you look at it, is that on the user interface there is a keyboard with a line going across it that apparently allows you to make the filter and “overtone” react differently to different keys. While this is a neat feature, I’d love to see the ability to turn it off or an easy way to reset points on the line. StringZ2 is loaded with a variety of presets and some of the presets make great use of the keyboard-image filter.
So for features, it has a bit more than you expect, for example is the feature I just mentioned, but also there are 2 ADSR envelopes (one for volume and one for time). There are also reverb and a lot of other useful parts that are pleasant to look at and easy enough to navigate. As for stability, you see, I’m running a dual core computer and this VST is made with SynthEdit. And as with all SynthEdit creations, I can’t run more than one instance at a time or everything gets buggy. But I believe this limitation is worth it, and those not on multi-cores should not have an issue.
As for cost? This is free, it's unique, and it’s great.