This is an excellent monophonic "Top Shelf" synth. Evolver sounds great and has "Dave Smith" written all over its many, many creative options. I have only had it a day and can say it is loads of fun to program and use. You can use it alone (sequencer), with a midi keyboard and as a stereo audio processor (there are inputs for guitar/drum machine etc..) .
At $475.00 Evolver is already a hit. The build quality is excellent - It is built like a tank.
Check it out: http://www.davesmithinstruments.com