There is a misconception that all subwoofers are more or less the same. Maybe it's because we've all had plenty of directional bookshelf speakers and can easily tell the difference between good and bad sounding speakers. On the other hand, subwoofers are a bit of a mystery and somewhat harder to immediately judge. Bass frequencies aren't directional so you can't just put your ear right in front of the driver to hear the difference between two speakers. Whatever the reason, avoid the situation in which your great monitoring environment is needlessly degraded by a less-than-ideal sub.