Learn both.  I have and here&#x27;s what you&#x27;ll learn:<p>React is clean but heavy.  It can solve every problem for you well except one.  That one is mobile web-apps.  (It&#x27;s really heavy for low-bandwidth applications.)  React won&#x27;t make you much of a better developer itself, but all the things that it comes with are really good to learn like:<p>- Redux
 - ES6&#x2F;7 with Babel
 - Webpack (which I prefer) or Browserify for packaging
 - Using ESLint to get in the habit of writing readable and consistent code.<p>Mithril is nimble and light but more difficult to use well.  Learning Mithril will make you a better developer because of how it encourages smart use of Javascript.  This is easier to see for yourself (read the blog entries) than quantify in a list like I&#x27;ve done with React.