Bootstrap 3 has been noted as one of the most reliable and proven frameworks and Mobirise has been equipped to develop websites using this framework.
One of Bootstrap 3's big points is responsiveness and Mobirise makes effective use of this by generating highly responsive website for you.
Google has a highly exhaustive list of fonts compiled into its web font platform and Mobirise makes it easy for you to use them on your website easily and freely.
Mobirise gives you the freedom to develop as many websites as you like given the fact that it is a desktop app.
Mobirise comes with huge collection of pre made layouts to help make your development faster.