The bad things are that it take some time to fiddle with the settings to get working, extremely high noise level plugging an electric guitar into the 1/4" jack, Microphone pre-amp is not as strong as advertised, Noise was evident in headphones when usb bus was attached to computer, Poor sound quality.
A Hi-Z (Hi Impendance*) input means its suitable for guitars / basses or even microphones. When i say 2 Hi-z i mean i want 2 inputs for guitar.
*google it (High and Low Impedance Signals)