I love by Dream Machine Pro. Seems to just work and keep everything up to date. I have it running my security cameras as well and it has been pretty much bullet proof.
What needs do you have for a router that the Cloud Gateway is missing or is bad at? A PiHole equivalent is about all I can think I'm missing.
I really like the DM Pro and have it deployed to an office of about 50 people. It's a pretty no-fuss solution and fairly simple to manage.
For my personal setup, I decided to go with OPNSense and I couldn't be happier. Much more control, at the cost of being a little more hands on.
I think the best (rough) comparison here is MacOS vs Linux (or more accurately in this case, FreeBSD).
+1 for Dream Machine Pro. Own one at home and have stretched them pretty far in SMB environments.
I use it with 8 APs in a mesh and a few switches, all UI, and it just works. I also have a lot of success helping out some local SMBs by setting up UI for them.
My UniFi Fiber has an adblock integrated, wouldn't UDM also have it?
IPv6 support is basic at best. The zone-based firewall is very prescriptive and limited. ACL stuff is not great. To increase the MTU of the physical interface connected to the ISP I would need to hack a systemd unit that did it on boot (I either need it at 1508 so the PPPoE interface uses 1500, or I need to MSS clamp it and have it effectively reduced to 1492). Initial configuration requires the device to be connected to the Internet.
There were a few other niggles, and in the end I just found it easier to do what I need on OpenWRT.