Live Composer’s main difference is that the editing panel of widgets appears on the bottom of the page. Live composer is also 100% open source, and is built by an experienced team of web developers. Live Composer doesn’t leave a lot of shortcodes behind when the plugin is deactivated.
After installing Live Composer the first thing you notice right off the bat is that it added 6 custom post types to my admin: Downloads, galleries, partners, projects, staff and testimonials. This can be seen as to obtrusive for many users, as it takes over a lot of the WordPress panel real estate.