We are always on the lookout for new and useful test equipment to add to our lab, and one of the things we have always wanted was a decent audio analyser. Although we have a couple of external sound cards which have been quite useful, nothing beats a dedicated audio analyzer, so when a Prism dScope III came along at the right price we jumped at the chance and purchased it. The Audio-Precision APx555 at $28,000 USD was way out of our budget and save for a few dB less dynamic range, in terms of over all features and customization, the dScope III offers everything we need a plus a whole lot more. We have already used it to chase down a few illusive issues in our existing preamp design and incorporated the changes in our new Preamp designs. Such is the benefit of having access to the right test gear ;)
(http://www.analog-precision.com/images/Amplifier/dScopeIII.png)