I will always preference wired over wireless, but I am currently unable to run an ethernet to my desktop (my partner is not keen on having a tripwire run straight across the house). So I did the same ping test that OP did and noted a few spikes, I had 10 pings over 250ms out of 600, all of these were distributed unevenly over time. Guess I could be subject to such wireless degradation. But I can't say for sure without trying an ethernet cable.
t : ms
32: 1725.0,
33: 662.0,
68: 406.0,
100: 980.0,
101: 285.0,
312: 454.0,
342: 746.0,
464: 453.0,
480: 1852.0,
481: 841.0