The higher end Drayteks lose the advantage of having a built-in DSL modem. I used to run two sites with Draytek 2860 routers on VDSL with 4G dongle backup and it worked extremely well. The older Draytek 2850 actually has two separate internal modems - one ADSL and one VDSL and both could be connected to different lines operating in parallel or failover mode. That's very
In this case I'll almost certainly be using a WatchGuard firewall with SD-WAN.
There are a number of benefits WatchGuards have for the sort of setups I run including being able to establish VPN endpoints with a virtual tunnel interface. I'm pretty sure that's not something Draytek supports on any of their products. I certainly can't find a way to do it on the 2850 I'm about to swap out. I can do it on Ubiquiti very easily and Cisco supports it too.
One really major downside I've found with Draytek is that there's no way to create or edit a configuration offline, only connected to a live device.
I had one situation where a very complicated Draytek running configuration was corrupted which caused certain services to fail in a reproducible way. Doing a factory reset and uploading the backup configuration reintroduced the bugs because the downloaded configuration file was corrupted too. It's a propietary binary format and there's no way to fix it now that Draytools doesn't work.
Draytek's support could only suggest a factory reset and start building the configuration from scratch on the live device.
That's not easy remotely.