We needed to upgrade from 10.22 to 2019.05. I chose to do a clean install. I hadn't done most of the setup of 10.22 and I wanted to learn the details. The customer didn't want downtime and I could not give a time frame. I was able to create packages of the configuration and most came over. My zones did not, even though the output of the load said it had. I don't know where they went. If you have a lot of zones recreating them would be a pain. We also had several DFPs. I have encountered some issues, but the learning and fixing has been well worth it.
Some warnings. If you use NTLM to connect to remote SQL database you will need a hot fix. The wizard doesn't work otherwise. If you have a CA the passwords you put in during the install/configuration are not used. The configuration has default passwords. I had a problem changing the passwords using the jmx-console. There is a script to make the changes, but the documentation is wrong (don't add spaces between the arguments, like -fxxx and not -f xxx).
From an admin GUI there is no difference. From a browser GUI it looks and runs much better and has more functionality.