BTW, I should point out that in the board I recommended, I am not sure that the Intel board will send audio via DVI to HDMI adapter, so if HDMI audio is a requirement for you, you are probably better off with the ASUS or step up to an Intel DH67BL.
Quad Tuner simply means four tuners in the device. In other words, the device can tune four different cable channels simultaneously. This article may be helpful to you.