I must admit to buying these as spacers to raise my Achat12 above head height above some 2x18 subs, as they were cheap and light, with no intention of actually plugging them in.
When I did get around to actually trying them, I was amazed! They are not the most efficient of boxes, but they sound as good as anything that I have tried out there and I have been doing live sound professionally for 25 years. Being an 18" driver, they were never going to be compact, but they are very light and easy to move with the optional wheels. Using an amp rated at 1500w a side into 4 ohms, they just keep on delivering a great bottom end without complaining, inside or out.
If you have the space, buy some. You will not be disappointed!