Hello @LineMoon,
I think several of your questions are having good answers.
The migration of the EG projects are quite easy and much quicker with the Wizard than without the it, they only need some special attention during the mapping step.
If you have a folder (or set of folders with the EG 4.3 projects (and dependent files) my best sugestion is to create a copy of those folders to a different location. Then, with the EG Migration Wizard, update the copied projects to the new locations. On that way, you can always have your old projects, compare, and have a good rollback option in case anything fails.
And, about the EG projects, well, the main advantage is to be able to be in control of your Flows and it is an interface that can be understood by anyone. Data Integration does the same job, and with better control, but then you need additional skills.
As disavantage, probably the only one is that EG projects are binaries instead of readable files, and you need to migrate them. but with the Wizard the job is really easy.
... View more