Micro Phone Home
The microphone is attached to the left side of the headphones and can be swung up and down, if you're not using it or need to adjust its position. It is firm and resists moving from a casual touch, so you don't have to worry about constantly having to fix it in place.
The sound quality of the mic is clearly inferior to that of a professional, dedicated microphone, but compares favorably to the cheap stand-alone kinds usually sold to computer users. Fortunately, sound quality is rarely an issue from the microphone, since the compression codecs on TeamSpeak or the like do far more damage than the mic itself.
One issue that I've always had with microphones, and the Plantronics Audio 90 headset is no exception, is that it's difficult getting sufficient microphone recording volume without increasing headphone output to uncomfortable levels. Perhaps it's simply a matter of my ears being tuned to quieter sounds, but it is difficult achieving my desired level of headphone volume while making sure my online buddies can hear my voice - unless I speak very loudly.
On the plus side, the headphones are very ergonomic. They may not be as comfortable as Sennheisers, but they're nicely padded, fit over even my over-sized head well, and even after hours of use there is no discomfort. This is by far a preferable solution to a one-ear headset or the earbud+mic solutions peddled for a mere $10-15 less.
The Audio 90 headset is also very durable. I made a little white lie suggesting this is the first pair I've owned. I actually switched months earlier after trying them out at the Rome: Total War event in Las Vegas. That set survived abuse for months, with the rollers on my chair legs going back and forth on the cable cord, the headphones being tossed aside after a frustrating match in a game and so on. The only reason they failed is because my cat chewed the mic cord after getting overly playful.
Contrasting the abuse these have survived compared to the gentle (if constant) use my Sennheisers got, there's little question about me switching back. Though perhaps one of these days I'll buy another Sennheiser cable again, those headphones will be reserved for occasional music sessions, not my constant work/gaming. It's hard to justify a cable that's more expensive than an entire headset that comes with a microphone to boot.
There's really only one major gripe with the Audio 90 and that is the really low-quality amplification offered by the volume knob on the cord. I'm sure I'm not the only one who'd gladly pay an extra $10 for a better solution, especially one that included independent microphone and headphone volume adjustment.