I have one, haven't had a chance to install it yet though. From all I read about it in the manual on from other users it is awesome, especially for fine tuning a three way front stage. That is what I will be doing with it.
I lucked out and got a brand new PowerClass series one. This guy had bought it back in 98-99 and never even installed it. Origianl box, manual, everything..... and mint condition.