[sdiy] John Hardy discrete op amp

[cheater cheater]

Hi guys,
has anyone used the John Hardy 990 Discrete Op Amp in their designs?
How do they perform? Are they good for very hot mixing stages such as
in mastering mixers?

Other than them being real expensive, would it be feasible to, for
example, build a filter out of those?

http://www.johnhardyco.com/products.html
http://www.johnhardyco.com/pdf/990-2007.pdf

Thanks,
D.