This subwoofer seems very solidly built, works and sounds well.
I am using this sub to extend the bass response of a pair of 8330 monitors, which I am using as a home stereo system in 25 sq. m room. This not only relieved the monitors of having to produce bass frequencies, which probably resulted in clearer sound with decreased distortion, but it also enabled to solve the bass problem in my room. With the fixed position of the monitors and listening position, you can move the subwoofer around the room as much as the cables allow and find optimal position for it.
The calibration is an extremelly usefull tool, expecially in the bass region, where the room response can extremelly boost some frequencies.
As a result of being able to move the sub to the optimal position and calibration now I have flat bass response from cca 23 Hz to the crossover frequency (80 Hz). I bet not even a lot of studios have such a good sound as the one I have now.
Even this smallest subwoofer and second smallest monitors play better than any non calibrateable passive system for any price could, with the sound level of course limited by their size, but I would not be able to play louder anyway because of the neighbours.
I am very happy with this "small" 7350 sub and the whole system.