About the Network issues: something similar happened to me yesterday. I just moved to a new flat and my Internet connection went from 50MB/10MB to 10MB/1MB and if Backblaze starts a backup with the Automatic Throttle option on it just takes the whole upload bandwidth killing every other connection and rendering the connection unusable for the rest of the network.

I don't have any QoS set up on my home network, I found two fixes: running the backup manually before going to sleep (maybe I can create an Apple Script and just cron this) or turning the Automatic Throttle off and giving it the minimum available (for me) 20kbps.