Well, in relation to those positive Phoenix reviews, were they used in combination with an optimized renderer. The Innuos Zeniths don't have optimized rendering, only the Statement does, adding the Phoenix to that would be redundant.
Quality internal renderers already do what Phoenix does. The reason Phoenix has good reviews is because they're being used with less than optimized rendering. I doubt you'll ever see Phoenix partnered with servers like Wadax, Pink Faun, Taiko Extreme, certain models of Antipodes. At top end of servers, no need since they essentially have a Phoenix built in to them. For the mid price and lower server with non-optimized rendering, the Phoenix would likely be of benefit. I contend, along with others, that a streamer/renderer does the job better than the Phoenix or any usb filter/cleaner device. A quality streamer is going to do a much better job rendering vs the server without quality rendering. The quality steamer cleans the network, filters and clocks the usb (doing the job of Phoenix), and renders better than those servers. Bottom line, you're getting far more bang for the buck, three functions for the price of one!