I used to have the 10" Velodyne DSL-R model, and it was nice, but I went from that to the 20-39 PC+ and it was a night and day difference, but I know with the 15" version, that will be a big difference. I think you will get better sound quality out of the SVS, but the velodyne may be louder. I also didn't really care about the DSP modes on the velodyne either, but if you do get it, I think the classical setting seems to be the flattest. I would personally go with the SVS, either one of them will suit you well. I know they gave the new NSD cylinders a deeper tune, but the older PCi will still have plenty of output, and play plenty low. Plus you just can't beat SVS for customer service.