Upgrade to Drupal 8 or wait for Drupal 9?
Go back in time and you’ll realize that every Drupal version upgrade has been drastically different from their predecessors. This caused compatibility issues and upgrade between major versions has always been a complicated task. Contributed modules and themes needed to be upgraded for compatibility, content migration was a hassle, and the list goes on. Gradually Drupal has adopted semantic versioning which allows for continuous improvements without waiting for major version launches and allows for a more continuous upgrade.
Be rest assured that upgrading to Drupal 9 in June 2020 will be a cakewalk!