What are some alternatives?
When comparing Live.js and Prepros, you can also consider the following products
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Koala - INTELLIGENT LIVE CHAT FOR EFFECTIVE CUSTOMER SUPPORT
LiveReload - LiveReload 2 proudly presents… The Web Developer Wonderland. (a happy land where browsers don't need a Refresh button). CSS edits and image changes apply live. CoffeeScript, SASS, LESS and others just work.
Fire.app - Fire.app is a menu bar only app for dead easy HTML prototyping.
Browsersync - Browsersync makes your tweaking and testing faster by synchronising file changes and interactions...
Compass.app - Compass is a stylesheet authoring framework that makes your stylesheets and markup easier to build...