gnostic19

I am looking for an amp and would like to go with a portable(Zen Head, Mustang, ELO Mini3, etc) but would consider a desk-top for $2-300 if the sonic advantages were there. Do RCA inputs amount to better sonics or to the guts of the units decide that fact? And do desktop units have better parts, necesarily, than portables? The desktops units i'm considering are the new Trends, and any other that are priced $2-300. thanks