Hey Nick_W,

QoS is only between the gateway and your MQTT broker, not between the modules at this time. We are working to implement QoS between the modules and the gateway down the road. You are correct that right now, the modules send their messages to the gateway but there is no guaranteed quality of service just yet.

Not sure why beacons would get through, but not mqtt messages - other than the fact that beacons are small, and mqtt messages are long...

This is most likely due to the frequency of beacons being sent. Due to the location of your gateway now, you are probably missing the same percentage of messages and beacons, but beacons are sent more often (in default mode) so it would appear that more of them are making it to the gateway.
We did just release new firmware today for the mcGateway and are soon to release a new mcGateway application processor. While the latest firmware updates should not have affected how the WIFI works on the gateway, I would suggest putting the latest updates onto your gateway (and modules) and then try to connect via WIFI again to see if it makes any difference.

Unfortunately, there is no warranty on the Kickstarter gateways110 as they are for development/experimental use. We do have the mcGateway110 available for purchase on our website right now.

We will be releasing the new mcGateway120 when available (more details to come soon) and that will have a standard manufacturers warranty. Thanks for your patience