I received my pair of VSD1S yesterday and did a quick listen and comparison with my pair of gr07 mk ii. The VSD1S is a real winner, at just $45 and free shipping from lendmeurears. Source used was my peachtree dacit -> uha-6s mkii OPA209.
On first listen, I felt that the VSD1S is a very balanced sounding IEM. Its mids were a little recessed and the treble was slightly higher than neutral though, compared to the my UERMs. Its soundstage and instrument seperation isn't anything to rave about, but that is typical of low-end entry IEMs. It sounded kind of closed in compared to the gr07, and especially the UERMs. Bass and treble extension was pretty good, and smooth throughout. I felt that the bass was just about right, similar to the gr07's bass but not as detailed or controlled. The treble was pretty even throughout unlike the gr07, with no serious treble spikes and very little sibilance, unless it was already in the track.
I found that the stock default tips fit me very well, but I do wish that they could be worn over the ears rather than just hanging down.
Overall, I think vsonic is pretty accurate when they say that the VSD1/1S retains 80% of the gr07's sound at only 1/3 the price.