The specs are great -- range, frequency selection, indicators are useful and easy to read, the devices are versatile and all the equipment looks great. Everything works as described.
Once we put the devices to work, my disappointments began to mount. The handheld microphones are usable, but electrically noisy. I would not use the for an application requiring high-quality sound.
The body pack microphones -- our church stopped using them. They are electrically noisy too but worse, the units are constantly cutting out. The headset microphones and the lavaliere microphones are interchangeable and connect to the body pack via a screw-in connection which is good, but it still cuts in and out frequently additionally, the connections add even more electrical noise (especially when moving around). Reinforcing the microphone body pack connection has helped slightly but we are looking to replace our DU4004 after less than 6 months.