That question is relative to how much data you have to migrate and your platform of origin. Overall, it’s extremely easy to migrate to either platform. They both offer migration wizards, walkthroughs, and a library of resources to help you get started. Also, both platforms have migration services available to help users with a more complex migration project.
However, if you read through reviews online, you’ll find many instances of users complaining they couldn’t migrate everything or certain data points didn’t migrate correctly. To that, we say you can expect some issues with nearly any migration, but it doesn’t change the overall ease of migration score.