I have one and I'm pretty happy with it, but it took a little work for me to be satisfied with it. Like previously stated, their mounting system sucks, you have to seal the wires going into it, and it takes some work to stop it from vibrating. I had to use a lot of dynamat behind the interior panel and where it attaches to the rest on the interior and I used expanding foam behind the actual enclosure to stop it from vibrating there. It vibrated like crazy when I first installed it like the instructions called for. I figured it would but I gave it a shot.
I'm running a Kicker competition 4 ohm dual voice coil 8" in it, the specs of that speaker were perfect for that size, sealed enclosure. I'm powering it by an Alpine 150 watt RMS amp under the front passenger side seat. It sounds great and has a good amount of bass for one 8. I was impressed. I have a newer Alpine headunit and I really like how I can adjust the sub level right on the stereo. Its nice to be able to turn it up or down to suit my mood so easily.