As one might expect, these Sennheiser's feel very well made as illustrated by the microphone which has a supremely smooth and steady hinge mechanism. It's a shame though that it isn't detachable. This rather restricts the potential alternative uses, and though one could use the set with an MP3 player one could hardly imagine sitting on the train and not looking just slightly silly. But, given this set is intended for gaming, it's hardly worth giving this disappointment too much weight.
Once you start using the PC166s one can immediately appreciate the clarity and general quality of the sound produced. Most parts of the musical spectrum are well handled, with a particularly nice balance between the mid and high low range. Bass, however, isn't quite as impressive. Though the overall sound is warm and bass well defined, the low range isn't quite as pronounced as it could and ought to be with a distinct lack of punch and power.
What the set does do well, however, is creating a good sense of immersion and this becomes more apparent when watching films or playing games. In the case of games this means being able to quickly identify the location of potential positions/direction of incoming fire, enemies and other hazards. Here the set excels, producing subtle sound effects with a high level of clarity and accuracy.
But, while audio performance is generally very good, it’s the microphone that really impresses, combining superb clarity and impressive noise cancelling to ensure you can be heard by your team mates. Unlike the microphones on cheaper headsets which are often too quiet and rather muddy, the volume and clarity provided by these Sennheisers is nigh on faultless. Consequently, whether you're gaming or Skpye calling, the Sennheisers won't let you down.
Indeed, the only real barrier to getting this set is the price. Overclockers UK are currently selling them for £58.74 inc. VAT, which is a superb price. But this is by far the best price I've found, and elsewhere you'd be hard pressed to find them for less than £60, some retailers are even selling them for £90 to £100. Even the Sennheiser PC165 USB which, by all accounts is identical, will set you back at least £80. At the Overclockers UK price I wouldn't hesitate to recommend this set, but for £70 or more the choice is less obvious. As a result if you can snap these up at the current price then do so because it's a complete steal, but if paying more the choice isn't quite as clear cut.
Great design, features and performance make the PC166 USB Headset an obvious choice for the discerning gamer that requires the very best. Depending on price they're great value too, though availability is sketchy at best as is pricing which varies considerably. Still, if you have the money you can't go too far wrong.