Monoprice makes three similar subwoofers with different sized speakers. This is a review for the Monoprice SSW-12 with the 12 inch driver.
The first question everyone asks is- is it loud? Yes, it's loud, and it produces very low frequencies. They claim a frequency response down to 20hz, and though I didn't pull out my audio analyzer I don't doubt it can achieve that.
What does it come with? The sub, of course, wall mounting brackets (don't try and lift the speaker by these as they're slide on, slide off) and drilling template, a floor stand, manual, and a set of RCA to RCA cables.
How's the sound quality? Here is where it starts to show some weakness, even if you take the time to carefully tune the roll-off on the crossover. The sound quality isn't bad, but it isn't stellar, either. It's a bit boomy, and not terribly precise. If you're looking for seat rumbling SFX on movie night you'll probably love it. If you're looking for rump shaking bass for hip-hop you'll probably like it. If you're looking for tight, controlled, accurate bass for orchestral music or blues you'll probably be a bit disappointed. I've heard it's difficult to get good bass in a flat-ish, limited space sub, but I know it's possible because Yamaha used to produce a (now, sadly, discontinued) wonderful little sub in the same price range that produced incredibly realistic bass, although it didn't go down to 20hz.
Still, because of my space limitations I was planning on keeping the Monoprice SSW-12 if it wasn't for one annoying habit. Like most subs it's designed to turn itself on in the presence of a signal. Unfortunately, it would turn itself on at random with a little 'thud' several times an hour even when the audio system was off. So, unfortunately, I decided to send it back. I'm not sure why auto on and off is such a problem for speaker designers. I've got a Harman Kardon sound bar that requires a ridiculous volume level to turn on, and literally turns itself off if there's a long quiet scene in a movie. Then there's this, which apparently turns on with the slightest electrical anomaly. I wish somebody would get it right.
In summary, if you want low, low, low- lows, and you can live with them being a bit sloppy, and can also live with it reminding you it's there two or three times an hour when your system is off, you'll probably like it. If not, then keep looking.