The world of USB microphones is exploding. Last time we checked, there were 14 USB mics listed for sale at our favorite online retailer. MXL has several models, and the top of the line model is the model 009. MXL states that this is the world's first 24-bit 96khz USB mic. No driver installation is needed, the mic automatically shows up in when plugged in to a Mac or PC.
If you are using one mic at a time, you can't beat the convenience of a USB mic. Just plug it in, select the mic as an audio device in your recording software, adjust the gain using the knob on the front of the mic, and you're ready to go. The only thing you can't do (at least not that I'm aware of as of this writing) is use more than one USB mic at a time. In OSX you can create an "aggregate device" which lets you combine several audio interfaces and use them as one, but this mic doesn't support that feature so you're stuck with one at a time.
Rather than describe how this mic works and sounds we’ve made a short ProductSpotlight movie of the MXL USB.009 that demonstrates the mic on guitar and voice. Check it out at HowAudio.com.HowAudio.com