A dedicated server is a computer in a fancy box. The folks making the well-regarded, dedicated servers typically pay attention to improving things like processing speed, power supply, fanless operation (i.e., quieter), optimized programing, EMI/RFI resistance (i.e., better cases and isolation), damping, clocking, and dedicated outputs like the JCAT XE or Femto cards. However, more important than simply putting a bunch of better "stuff" in a box, the people who have been building servers for a number of years (like Mark Jenkins at Antipodes or Benjamin Zwickel at Mojo, and of course the other well-regarded designers) have found ways to continually improve their products to create quiet, reliable, great sounding servers. That experience, expertise, and of course the premium parts and execution are what lead to the great sound and the premium pricing. "Blown away" is a matter of personal perception.
