CKEditor will be the default editor in Drupal 8 and is currently the most popular editor in Drupal 7.
However, in some respects, CKEditor isn’t very tightly integrated into Drupal. For example, it’s not able to access Drupal images or link to Drupal content.
The Linkit module is the best way to improve linking.
Linkit provides an auto-complete field for linking to nodes, users, files, terms, and fields. Linkit makes creating links significantly more user-friendly.