The other day I got my Nessie microphone from Blue. The Nessie is an entry level $99 USB cardioid (unidirectional) mic with a built in shock mount, pop filter, serpentine neck, and non latency headphone jack. What all of that means is that it is probably the best entry level USB microphone you can get for the price. It's aimed at podcasters, folks who do presentation voice overs, and people who want their Skype chats to sound really good.
Structurally, the only major criticism I've heard about is the plastic neck. For me the way the plastic is molded provides a strong, light structure for the microphone, allowing it to be more stable, less top heavy, and less likely to get knocked over.
The metallic dark ring at the base provides the majority of the weight for the mic, it also acts at the volume control for the headphones, twisting it right or left increases or decreases the volume. Above the volume control is a touch control mute button. Just touching it allows the user to mute the microphone without the sound of a button click messing up your recording. Another cool feature is that when the mic is on mute the light ring below the volume control strobes.
On the back there are three switch positions: raw, vocal, and music. Raw does no audio modification, vocal modifies the audio for voice recordings, and music is for live instrument recording.
There is some debate about how any USB microphone can be unidirectional. When using my headphones with the Nessie I did pick up my ham fisted coworker banging away on his keyboard, but when the audio was imported none of the background noise was picked up. So that was nice... I've used other blue mics before like the Snowball but I think I get better audio quality with less echo using the Nessie. All in all for $99 dollars the Nessie is a really good deal.
In conclusion, and if I'm honest, what I like best about this mic is the way it looks. I love it's dieselpunk aesthetic, and it looks great standing on my desk or next one of my old radios.