The ability to customise your institution theme is a nice little feature where you can select colours and a logo/crest to upload. I was training some new users last year and saw @kieranphilip build a nice looking theme for his school in 3 minutes.
Along with theme customisation you can now also select the 'primary theme' which takes away the standard 3 boxes and introduces a nice UI for Primary school pupils.
Great for engaging younger users as they can click on the pictures to access different areas. (see picture)Dropdown menus are a new feature that you can turn on in Mahara 1.5 that will help users visualise and find different areas when using Mahara.
If you know enough about coding and design then you can still apply your own skin.
