The PC12-NSD was not as easy to blend ito my older Klipsch system as I had hoped. The best setting I used was to set my crossover in the reciever to 40Hz and only allow the sub to fill in at what my mains were not built to reproduce.
After a month of playing music and movies on a daily basis I can say that I feel it was perfect for the room and met all my needs. More sub would be overkill. All the positive things that have been said about this new version are, in fact, true!
I would like to point out one negative thing that has not been mentioned.
The overall weight of this sub is not enough to prevent it from "dancing alone" on a smooth surface floor. At levels at or above 85db with only the 40Hz and lower being fed to it, it will move around the floor till it finds a resting spot againt another piece of furniture or a cable pulls tight restricting its movement. This is only noticeable to any degree while playing music due to the extended amount of time the sub is active.
I have access to 1-1/2 inch steel plate and will have an add-on base plate built to be mounted to the bottom of the orginal base. Using a little elbow grease, a grinder, some paint, and countersunk machine screws from the bottom of the plate up thru the base of the sub it should be enough weight to "hold'er down". As it stands now, it's hard to tell if it's bass or the sub pounding the floor.
Other than that small problem I feel it was the best sub for the price, and would buy it again.