I bought it last week and first impression is, its an amazing piece of VST plugin.
How it works is this. If I render all my audio panned dead center. I can mix each audio track through multiple instances of this plugin (one plug per instrument group) and place the 'instruments' in a virtual stereo field that adds delay, panning, and dynamic level compensation based on where it is in this 3D field. It was a little hard to do at first, since there was no guide to follow, but I photoshop'ed up a little orchestra diagram to follow and I placed the instruments in the field using my diagram. The results were pretty stunning.
Just wondering if anyone else had tried anything similar to this, or if there were other programs that did this type of thing. For GPO, it really isn't necessary since the instruments are panned very well out of the box, but I'm always looking for other ways of reinventing the wheel.
I can post a picture of what this thing looks like if ya'll want.
Thanks for the tip on this Joseph - the demo is certainly worth playing with.
In answer to NeoTypic's question - do the following in Cubase [see diagram for steps]:
- don;t put the plug in on the global stereo out
- assign the channels you are interested in panning to your VST instruments as usual (eg GPO)
- start your song playing [if you want to hear the effects immediately]
- go to the VST CHANNEL MIXER (1 or 2) [under panels menu]
- scroll to the channels you are interested in, and click the INSERT button at the top - this will bring up a new Channel Setting window. 
- to the right of the fader on the Channel Settings Window is the INSERTS strip - pick 3d panner from the drop down list [under the ON / EDIT buttons] 
- click on EDIT and then SHOW PAD in the pop up window 
- move the channel around whereever you want 
- repeat  to  for other channels and each one appears on the same PAD
[ you could of course additionally put instruments into GROUPS and pan the group for a simpler arrangement]
3D Panner Studio is a very cool plugin. It uses 3D HRTF tecnology which is great for intereactive games and other applications. This is a little different than the usual panning one hears in concert halls and recordings, but still a great audio experience.
I'm surprised that no one else picked up on your placement of the First and Second Violins in your graphic! The most usual disagreement about where the First and Seconds go is [a] First most outside on the left, with Seconds next inside (i.e., the reverse of what you have) or [b] First on the outside left and Seconds on the outside right (with Celli next in on the right and the Violas somewhere in the middle-ish). I generally prefer the "b" arrangement since it allows for more antiphonal play between the First and Seconds.
Also, from a stereo point of view, you don't usually want the Double Basses to sound too right (most folks feel that low frequencies don't really have that much directionality anyway) so I usually "cheat" them a little more towards center. I'm looking forward to trying the 3D Panner Studio "trial" version, but I'm also chomping at the bit to do more discrete 6-channel stuff. It's all good!