AMD systems have great prices(while they are "slower" compared to Intels offerings, the performance per dollar seems quite good).
My Intel mATX board cost MUCH more(I wanted very specific features. $170 for a mATX board was rather high, then again by X58 board was $330...I spend WAY to much money on computers...), but I also had all kinds of selection(and price range).
I have slowly moved over to small systems after years of NEVER wanting to go under ATX. Do much has been integrated as long as I can get my video card and a sound card(I used the onboard audio for a few months, but did not like the features[some of the most basic features my old Audigy had did not exist on the "X-fi MB2" package].) into the system I am happy with it.
My media center is even mITX
. That is when I started working towards smaller less space consuming systems.