I will add that my experience is the same as Ronnie's in my meagre 9 zone system...I have had no drop out issues at all since SONOS helped me tweak my network...

Audio: Triad Monitor Golds, Surround Golds, Silver Subwoofers; Procella P-18 Subwoofer; QSC DCA 16622s, 1644, 3422, BASIS 922uz; ADA MACH IV B
Other: APC S-15s; Crestron
Sources and Video: Ran out of characters .....................