We have a specific need to use a mic connected directlly to our Macs to collect audio for web content voice overs. Up until now we have been using the Samson C01U Cardioid USB Condenser Microphone. I recently came across this cable that converts USB to XLR, so we can use any mic we have, which will be higher quality than the Samson.
Any pros or cons that anyone can see ?

http://www.soundtech.com./lightsnake/xlr10.asp

Here are the specs :
Resolution: 16 bit 48/44.1Khz
THD + N (-3dBr): -76.1 dB
SNR: 83.1 dB
Dynamic Range: 81.6 dB
Input impedance: 1M Ohms
Frequency Response 48KHz: 20 - 19.2K Hz
Signal Input Range: 0 - 2.88 Vpp
Signal Boost Gain: +20 dB

Some pretty poor numbers there, especially the S/N ratio. Compare the listed rating of 83dB with even a Soundblaster Audigy at 108dB or good quality audio interfaces at between 110 to 118 dB.

...I recently came across this cable that converts USB to XLR, so we can use any mic we have, which will be higher quality than the Samson...

Well, not really "any mic you have". Near as I can figure out from the web site, the cable interface does not provide phantom power.

If you have a dynamic mic that sounds better than the Samson, then you're in business.

If you're wanting to use a better-quality condensor mic, I highly recommend the M-Audio MobilePre USB, which will function as an external sound card with great specs and phantom power, too. I use one for remote apps with a laptop, it's great. Street price about $150.