I set up multi-WAN in a few small business contexts (on a Zyxel appliance, and on pfSense) and to be honest it was always a little flakier than I hoped. It was

I set up multi-WAN in a few small business contexts (on a Zyxel appliance, and on pfSense) and to be honest it was always a little flakier than I hoped. It was always failing over too quickly, or too slowly, or not reverting back to the primary WAN quickly enough when the failure/congestion cleared up. I think any sort of multi-WAN setup where you aren't actually an AS running BGP is doomed to be somewhat hacky. Of course running an AS is both a ton of work, and basically impossible for a residential customer anyway.