The version of Melodyne that came out not too long ago is called Melodyne Editor. Melodyne Studio is the big brother of "assistant" and "essential". You can buy only Melodyne Editor. But if you wanted everything Melodyne has to offer, then you spend more and get the Studio. If you buy Studio,they also give you the licence for the Editor version as well.

The DNA feature doesn't work based on Timbre though. Let's say if you have a flute and oboe playing the same note, it'll give only one blob to edit. Generally, it works better if the polyphonic track was recorded by one instrument. I had some good results with a string quartet once. Not great, but not bad either. It gets really confused when there's pitched and non-pitched instruments in the mix. If the mix and recording quality is great, chances of getting better results are higher. If the notes are streched too far from the original, you can hear the artifacts.
I primarily use Melodyne to make pitch correction and hormonizing vocal tracks, for small productions, church choirs ...etc In fact for the christmas concert, I used some back tracks, and the choir I work with sounded pretty professional!! Thanks melodyne!