Streaming: WiFi or wired??

Mahler123 is right.

Both wired & wireless will work excellent as long as they are working within their limits. The chances of wireless dropping packets and causing re transmissions are a bit higher than wired, especially if a lot of wifi devices are sharing the same band. Moving to the 11ac at 5G bandwidth may reduce those issues, unless you live near an airport or anywhere where radar signals are present.  This may cause the AP to change bands continuously (DFS).  Also, with higher frequencies (at 5G) , your signal degrades quicker so distance becomes more of an issue.  This is laws of physics and you just have to live with it.

99.999 % of the time, both will be fine :-) It is really a choice of convenience.

In this thread, I have read some references being made to "noise" in the PSUs and/or wifi signals. This is completely irrelevant.  The wifi signals (and hence the audio signals in the data packets) are carried in a digitized way and the PSU noise of the wifi and/or wired AP has ABSOLUTELY NOTHING to do with the quality of the analog signal you will achieve after it has passed thru your DAC.   Any AP noise issues will be automatically taken care of by re transmissions and CRC checks and error correction algorithms.

Cakyol

That is true however I have seen some network switch product white papers that claim network Wire noise can make its way Into the signal from streamer to dac where it might have an effect on jitter that might be heard in some cases. The switch is advertised for audio applications to address that.

That is definitely not an issue with wireless connections.

Also, with higher frequencies (at 5G) , your signal degrades quicker so distance becomes more of an issue. This is laws of physics and you just have to live with it.

This and the fact that higher frequencies penetrate walls poorly prevent interference from outside.  In addition on 2.4GHz band each channel is 3.5 channel wide, so in reality there are only 3 to 4 completely independent channels.  My microwave was on one of them causing dropouts, neighbor on another etc.  I've never had dropout, since I switched to 5GHz (less traffic, more channels etc).  With WiFi I don't have to worry about anything on computer side.  Receiver (Airport Express) has small jitter on digital output, but it is suppressed by the DAC (Benchmark DAC3).

@mlsstl, future proofing is a good point to bring up and one I really wasn't thinking about.