Our project was something that has evolved from a full web app into a PHP backend fronted by a reactish SPAish thing. Our spool up time to cache our website is 13 ms from a cold start (after provisioning and stuff) so we're pretty good at horizontal scaling. Once cached our overhead is 7ms for framework things. Our page load times across the board calvary wildly with 25ms being our target time but with some very large reports stretching into the seconds range - on those slow pages all those previous numbers are essentially irrelevant and performance is dictated solely by how much we're investing into query caching and tuning.

Personally I'm actually a big fan of PHP, it's incredibly powerful and good with lists (and all good programming is list programming ;P). The typing is strong when enforced and weak when you choose. The lambda and reflection frameworks are robust and it has a number of interesting phpisms like magic functions and variable variables.