It was a fantastic student language - the docs were great, the code was simple and imperative, there was loads of prior art online. It was empowering to tweak code and see immediate results in the browser.
These days I prefer the strictness and ecosystem of Scala on the back-end, and the developer-friendliness of ReactJS on the front-end. And I think the separation of concerns (model-view-controller) is helpful.
So I am gradually migrating caption.me PHP code to Scala/ReactJS. A migration like this can be done piece by piece. After implementing the back-end for a feature in Scala, I write the ReactJS component, then alter the PHP code to render the ReactJS component tag in place of the former PHP implementation, then use some simple javascript plumbing for the React DOM binding.
I have a Grafana chart that shows the number of lines of PHP code remaining, so I can track my progress over time. It's quite satisfying.