This is a Multi sampled instrument. The setup is as simple as installing the Library, opening up Kontakt or other host, locate the library and load your instrument. After that, you are making noise. The Gui is nice in the way that it looks very "vintage" and is designed to look like the original instrument. The bad part is that this makes it a little too dark and hard to see. I usually enjoy these "throwback" interfaces, but I would sacrifice the novelty of it all for an easy to read/use GUI. One nice thing about the interface has all the main control parameters on the GUI's face and they are nicely spaced and not crowded. As this is a relatively simple synth by today's standards, tweaking the sound is relatively easy and can yield awesome results in very little time.
I really enjoy the sounds coming from this instrument. They are surprisingly warm and full of Analog character. I especially like using this unit in Poly mode for some fuzzy/noisy yet warm and soft pads. I run this in Kontakt 5 on a MacbookPro i7 Core 8gb ram with an RME Fireface 800. The sounds suit all sorts of styles. I use it mostly in electronica and rock styles but I could see this used in almost every style of modern electric music. At least any place a moog or vintage sounding synth would feel comfortable.
What I love most is the simplicity and the sound quality of the Ondes. It can range from eerie string style pads to gritty fat leads to huge keyboard styles and it very easy to morph the sounds to achieve what you want. What I don't like about this unit is how much CPU it garbles. It's a small sample set, roughly 30mb loads up in my memory server in kontakt yet it still slams the CPU meter at 256 samples. This makes me use it far less than I think I would. I guess I may need to upgrade to a MacPro at home soon. $129 is a fair price to have such a unique (and rare) instrument in my arsenal. Although I have never heard one in person, I have heard several recordings of the Ondes and Soniccouture did a great job capturing it. This is essentially a basic synthesizer, so yes, I have used lots of synths in my day. In terms of sampled synths, this is one of my favorites. Yes, I would buy it again, but I might have waited until I got a Mac Pro knowing what I know now about the CPU consumption.