For me it was the stability. I haven’t tried OpenWRT, but OPNsense was quite troublesome. I don’t do anything exotic, just standard dualstack and some firewalling, but OPNsense at some point stopped being able to get the ipv6 interface up, with no config changes. I also noticed pings regularly spiking for no discernible reason. I tried to debug both for a few days and just gave up.
VyOS is Debian with effectively a single file config, so it’s both simple and rock solid. As a bonus, pings got a couple ms lower on the same hardware.
Huh, I considered BSD to have a good reputation for stability and I believe network stack performance as well. Too bad.
I did very much like the debian base of VyOS. I've had pretty good experiences with OpenWRT. But it's command line configuration isn't quite as polished as VyOS imo. Interesting note about the pings.
VyOS is Debian with effectively a single file config, so it’s both simple and rock solid. As a bonus, pings got a couple ms lower on the same hardware.