Bought for use with Eve Audio SC203 monitoring system. Despite overwhelmingly positive reviews i remained sceptical it would please me as a bottom end for casual listening and monitoring sound. Pleased to say this is a tremendous value for money unit - £130 vs £460 for the Eve TS107.
While i don't have direct comparison to more expensive studio grade subs as a casual listener/producer it is more than enough. Has a clean, punchy bass response which perfectly suits smaller monitoring systems such as Eve SC203. Without it I was missing a lot of low end, SC203 has surprising bass but little impact. Upon firing up the SUBmini sound immediately became much fuller. In my situation it sounds best with phase inverted (brings a warmer, bassier response) and volume around half way, though your mileage may vary.
So to conclude this is perfect for smaller monitoring set-ups where super deep lows and loud listening volumes are not a requirement. Clean sound and very well made unit for the money.