That used to be the case. Lately 3BB has gone down a lot for me and it takes them more time to fix it. I woke up to still another outage today. That's 3 in a month. The new router they gave me made the speed more consistent though.
I'm considering AIS 2GB, and use 3BB as a backup, but I think they may use the same lines now, so it wouldn't help. Does anyone know if they are on completely different lines?