Well the SVS uses a 12" driver for a start, which will move the same amount of air as almost 2 10" drivers of equal xmax ability. Then the SVS also includes the DSP function, which if you learn to use will improve the response of the sub as well.
The prices are about the same meaning on paper the SVS looks the better spec for the money, and its the one I would likely go for personally. In addition, the SVS website gives some nice details about the driver B&W dont give us, like the fact it uses a good sized 2" voice coil with dual shorting rings that reduce distortion, and a pole vent that reduces power compression effects from heat build up. The SVS also claims solid output to 20hz in room while the B&W states a -6db measurement of 23 or 28 hz dependant on how you set it up. In reality, this translates as its probably only good to about 30hz a good output levels, so the SVS takes that one on paper as well. There is also a discrepency with the B&W figures, it claims output of 500 watts with only 98 watts power consumption. This tells me it doesnt output 500 watts continuous and is likely less than half that in reality, more in line with the 100 watt consumption figure.
The top and bottom of it is, that I personally would choose the SVS out of these two.