I like that it's easy to use, has many different templates for logos, colors etc., is very affordable compared with other services out there, creates professional looking designs in minutes. It can take some time getting used to editing shapes manually - you have to be careful not to accidentally delete or move something else! The interface could do better at making things more obvious when they're selected/de-selected.
Also sometimes if an icon isn't available (for example "folder" instead ofβ¦