I finally decided to step up to a pair of semi-professional headphones,so these being my first pair of studio grade earphones,I don't have a basis for comparison to other similarly priced headphones...but these are my impressions in contrast to my pair of Samson CH70 earphones(which were only $25 new).
I had no clue how to shop for headphones,but the Q40's are well reviewed performance-wise,with a frequency range of 10Hz to 20kHz.I also like the detachable & replaceable cord & the compact folding design.
They are also a very sharp looking pair of ear monitors & choosing the same brand as my pc speakers seemed like the logical choice mix-wise.
The Q40's seem to give off the same audio characteristics as the M-Audio BX8a's....the bass range is deep & the mid & high range is moderate & comfortable & very detailed. 
The only thing negative that I have read about these earphones,is the reviews that I had found on the M-Audio website forum...in regard to the cord.
Apparently,the cord is very feeble & it does not hold up well at all and several people have attested to this,but I find it very odd though,because I've had my $25 Samson headphones for a few months now & they have held up very well......I just don't see how a pair of $150 headphones could be manufactured so haphazardly.
M-Audio will replace the cord if need be & the worst case scenario,is that I would have shop for a 1/8" mini plug cord elsewhere(without the threaded end).
The Q40's are bit heavy,but a sturdy feel is good.They become a bit uncomfortable after about 2 hours of use,but perhaps that's due to my rather large cranium.
At this point in time,I feel that the Q40's are a sound investment.
-Thom
