We are also a utility- sewer/storm, but have decided that the TN will work for us for now. Trust me, I feel you on all of this migration business, it's a lot.
We might in the future, move to UN, but because of the major shifts in schema and the general complicatedness of UN, we are giving TN a go. So far, it seems to provide what we want/need. I am still in early stages of migration to TN. I like that I didn't have to change up my entire schema, and could for the most part, easily convert the data from GN to TN. I would be happy to chat about what we are doing and the workflow we are using with you if you want? We still had to have the licensing for TN, so there is that. This is giving us the option however to get out of ArcMap and over to ArcPro.
The one thing that we have found that is a little irritating is that the up/down Trace widget that is in ExB will not work with TN. It is UN specific (I haven't tried to use it yet, but have talked to the ExB team and this is what they are telling me). This could be an issue for end users as they have gotten used to being able to run traces for themselves within our WAB Dev Apps.
Feel free to drop me a message if you want to discuss more about what we are doing.
Vanessa-