The performance of an audio device will always be hard to judge objectively because there are so many variables that are hard to compensate for. What I always try to do is put the headphones through a series of different types of music at different intensities to check how they perform under various circumstances.
The V-MODA Vibes are equipped with a normal dynamic driver with the impedance of only 16 Ohm. So I think it's safe to say that pretty much every type of audio device out here can drive them fairly well. To test the Vibes I used my Cowon iAudio i7 MP3 player and my PC which has a Creative X-Fi XtremeMusic (ASIO enabled) along with the Foobar player.
To start off with I listened to some of my favorite tunes, some that I have listened to thousands times and know all of the details in them. After listening to them for about an hour I had gotten a so and so impression of the Vibes. They are very bass heavy and tend to sound a bit muddy compared to what I'm used to. The bass was very present, but wasn't precise enough to justify the amount. The lack of definition continued up through the mids and the highs. When it came to listening to Rock and Classic the Vibes apparent lack of definition hurts the listening experience quite a bit.
The dynamics of most of my favorite rock tracks were ruined by the poor high frequency response. All of the little things sounded muffled and made the riffs sound weak and half hearted. Because you can't distinguish between different types of strokes on the guitar or intensity most Rock tunes will sound plain and therefore the listening experience will suffer greatly.
Overall the Vibes sound very soft and warm which actually made Hip Hop and R&B sound quite interesting, however, the lack of definition will still be apparent when using the Vibes in conjunction with a high end player. Since they sound so soft and have enough bass power to make you feel your ears are starting to fall off will probably satisfy even the most enthusiastic bass freak. So I guess if you are a bass freak and want a good looking pair of in-ears you should probably consider the Vibes just because they have such an immensely powerful deep end, but please bear in mind that midrange response isn't on pair with other midrange in-ear-monitors.