I use them for 2 years.
Material fantastic. The Tops 400RMS deliver continuously without flinching, ditto for the Subs. The four speakers deliver a sound pressure of 134dB SPL.
What I like least is the finish of the box style carpet, but hey, compared to the price there is no miracle finish aside, this provides a max.
For DJ's and sets of musicians who want a good return, the price is unbeatable.
It should be against them by adding a good amp, I use my Electro Voice CP2200 that delivers just the right power for these speakers, 500W / 8 ohms, 800W / 4 Ohms.