I use the same. I don't have any uptime requirements because it's only for freetime and experimental use. But I don't think there has been any outage (knocking on wood)
If you use their Ubuntu image it should have unattended upgrades enabled already. Still, you need to watch it. Ubuntu is not very good at restarting daemons after a library has been upgraded. dhclient is regularly affected. And libc is blocked from automatic updates IIRC. The kernel anyway, because this is a diskless setup.
I like the product (baremetal ARM). But I fear it's dead. They used to upgrade the kernel frequently, but now it appears that no one is working on it anymore. Of course don't try to run anything that requires performance or availability on a 4 EUR / month server.
