Over at the Mac OS X Audio forums there was a giveaway of String Studio VS-1 from Applied Acoustics and I was one of the lucky winners.
Now as an owner of Ableton Live Suite I already have Tension instrument (which is a joint development between Ableton and Applied Acoustics) so I sort of knew what I was in for. But there are some extras.
If you like presets, this thing came with many hundreds of presets (way more than in my Live library). Say what you want about presets, I find them useful tools in learning what is possible with a software instrument.
Additionally, it has built in effects. Live instruments are typically very dry because the intent is that you feed into audio processing modules that you've set up (which is very cool). However, as a beginner in the world of sound design, it's often easier for me to alter a fully fleshed out sound than it is to build one up.
There is also a built in arpeggiator that is different from the Live arp which is good (I'm not a huge fan of the Live arp [perhaps I'm just not smart enough]). I don't fully understand it yet but it seems to be a combination of an arp with step sequencer which makes for some coolness.
Finally, as a friend pointed out, I'll be able to use this in Logic which is a criminally underused tool in my box. (That is if I ever get to the point where it works properly for me -- the Logic 9 + Snow Leopard combination is having "issues" but that's a separate rant).
So thank you to Eric Thibeault who held the giveaway and to sandbags who poked me to enter.