I too agree with Steve Nugent. Servers are too new and they are constantly changing and being outdated quickly. My personal experience demonstrates the benefit of each mod for your server may pay dividends based on how the DAC (USB)/Renderer (Ethernet) implements the input hardware. The better the dac interface design, the less audible benefit gained from improvements upstream.
I have no experience with Antipodes but value Steve's insight, which has been consistently beneficial over the years.
Over on Jplay.eu a discussion regarding a to b comparison between a dual server (Control and playback) with Windows 2012 + Jplay + Audio Phil OS Optimizer vs. the $17,000 Aurender (which was offered at a discounted price) demonstrated marginal to major benefits on all fronts favoring the lesser expensive home build server.
The server for me is a continuous experience where I have changed and modified the server over the years at an expense well over most of these commercial servers mentioned in this thread. Honestly, I feel I should have just purchased an Aurender or Antepodes. However, to do so would limit my ability to adapt to new technologies.
Speaking with folks over in Asia, they have moved away from the sever altogether.
I personally believe part of the reason why Steve's Mac Mini sounds as good as it does is how well the ODSE implements the USB interface. Waversa also does this extremely well. Their Ethernet input is a magnitude better over their USB input. Because of this, I am favoring an internal Ethernet to I2S on the ODSX. Steve's external Ethernet to I2S with linear PS could be a major gain for dacs with I2s input.
With these dacs, the sound signature settings of Audiophile optimizer creates no sonic difference in my system. The USB cable was minimal change. $40 switch PS to Battery PS to LPS - minimal change.
My recommendation is this: find the dac that you enjoy most. Then if the USB interface is well designed, you will save substantial cash avoiding other improvements. If not, consider an Offramp 6 (YES, Six - it is coming soon) or Sonicweld Diverter before you make improvements in the server.