The biggest issue with moving to a different operating system is the files and data you will have to leave behind because the other operating system does not support it. Apple intends to make that process less painful by introducing a new Windows Migration Assistant that will pull more data from Windows to Mac.
The current version of the migration tool works only on data that are locally stored on the storage drive, meaning it will pull over files like your pictures, videos, documents and limited email and calendar information. The new version which will be coming to macOS 10.14 Mojave will support pulling data from third-party apps like Outlook as well as the local files and data stored on the Windows hard drive.
It would be nice to see a more advance migration tool for pulling over data from Android to iOS, especially with third-party apps like Whatsapp which is somewhat of an issue for users that cherish their Whatsapp messages and would like to see the same messages when moving over to iOS.