The 12.0 upgrade process still works the same as previous releases.
The time for each node to install the update and reboot has been improved. I am not sure by what percentage the upgrade is faster though.
Note: If you have not upgraded to 11.8 first and performed the full power cycle on H610S nodes, you can still upgrade to 12.0, but you have to perform the full power cycle on the H610S nodes after the 12.0 upgrade. This will add time to the upgrade.
If you have upgraded to 11.8 first and performed a full power cycle already, then you do not have to perform the full power cycle again for the 12.0 upgrade.