1. I wanted to use my own router instead of theirs. Turns out they send DHCP responses with VLAN 0 ethernet tags (which I guess is for 802.1p) which apparently a lot of DHCP clients don't understand at all. I tried OPNSense and Mikrotik ones and ended up having to apply a patch manually to dhclient that comes with OPNSense and recompiling it just to get an IPv4 address (https://github.com/opnsense/src/issues/114).
2. They don't provide native IPv6, they don't plan to provide native IPv6, they have a 6rd setup that is inaccessible by new customers, and to top it all off, from what I can tell they actively block 6in4/protocol 41 so I can't even use a third party tunnel.
3. Their tier 1 tech support at least knows what IPv6 is (the thing they tell people they don't support; they don't understand it beyond that). Their tier 2 support guy called me once but he clearly was simply relaying messages from an actual network engineer he was getting via text chat, so I got nowhere. Their tier 3 is their network engineers who have no time to talk to people like me since I never got a call I was promised from them and have no way to follow up except starting with the 800 number again (a literal multi-day process).
At least with city broadband I know exactly who works on the project and can go talk to the network engineer who can unblock protocol 41/unfuck the DHCPv4. /rant