Any reason to limit it to just those two?
Laravel is currently the clear leader right now in overall usage on new projects (https://coderseye.com/best-php-frameworks-for-web-developers/). For me, one of its big pluses is laracasts.com, as Jeffrey does a great job with his video tutorials on all aspects of Laravel and PHP. However, I've never used Symfony, and haven't used CodeIgniter for several years, so I personally can't really do much meaningful comparisons. (I use an in-house PHP framework at work that is a totally different animal, based on Java Struts. We have another team that uses the "Slim" PHP framework, as their overriding concern was performance, and they don't really need a lot of complex features.)