I have not used MOCA but it does intrigue me.
Another alternative to flaky WiFi - particularly with Squeezebox products which are G only, not N - could be a WiFi N adapter like Cisco-Linksys WET610N Dual-Band Wireless-N Adapter. Other vendors sell something like this too. Assuming that the adapter allows for 5Ghz, then that should bypass any local interference at 2.4Ghz.
I need to so something about this flaky WiFi:
WIFI N adapter for the SB devices?
sit on the sofa and quietly hum tunes to myself :-o