The Prophet VS is truly a unique instrument. The pads it produces are unlike any I've heard since. Although it's strengths are in it's rich pads and strings, it also produces excellent lo-fi analog nastiness. The unique sounds this unit produces is in part of it's strange digital/analog hybrid. I would say it is a combination of an Oberheim Xpander, PPG Wave, Sequential Prophet 5, all into one.
Although many will tell you that this thing can be compared to subsequent Vector Synths, this is still the king. A Wavestation sounds flat and pales in comparison. This is probably the warmest sounding digital synth you'll ever hear (minus all those new DSP-based virtual analog synths today). It's sound is something that hasn't been close to reproduced in another synth.
Get one today before the inevitable analog backlash! At one time these synths fetched up to $2000 per synth...but have since fallen in the wayside for analog/analog-emulating keyboards. They're rare and truly unique!
You can hear it's distinct sounds in many artist. Vince Clarke used it in some of his late 80's material. Trent Reznor abuses this synth exclusively in Pretty Hate Machine, Broken, and The Downward Spiral - and a bit on his new album - The Fragile. Brian Eno frequently used the synth for his soundscapes in the 80's such as the Shutov Assembly. All the microjam Chain Reaction/Basic Channel techno artists such as Maurizio use this synth extensively in their minimal compositions.