[sdiy] PC USB Spectrum analysis devices..

[Jean-Pierre Desrochers]

I'm about to buy what is needed to do spectrum analysis
on my modular filter modules using PC USB devices for this purpose..
I read a lot about all the available PC spectrum anal. software
that use available sound cards. Software like ARTA, Rightmark, etc..
seem to be good for this use. But I also found the QA400 USB audio 
analyzer
made by Quantasylum 
(http://www.quantasylum.com/content/Products/QA400.aspx)
that sells for $200.00 and uses proprietary software that avoid
Windows sound API and driver installation issues..
The QA401 upgraded device should even be better but still not released 
for sale.
Anybody uses spectrum analysis stuff ($200-$500) so far
that could tell about available semi-pro device/soft combos ?
Thanks