Avoid using it on production!
HTTPD + PHP has a memory leak, slowing the server down in time and crashing at some point.
It's US 13.3.2 here, but I don't know how far the bug goes back. Haven't tested if it's the build of Apache coming with the stack, or this version of Apache, or PHP.
Tried some different settings with 3 of our servers in the past 3 months. It was a disaster. The first 2 were some low end VPS servers so we thought it could be the servers. The last one is set up on a monster dedicated server with lots of resources after a format. The server was running another stack before with no issues for 5-6 years and we decided to use US for all our systems, due to it's better structure.
But now it's clear that all our troubles were this version of the stack. I was going to try a different Apache build with it, but apperantly we have no time for it now.
I don't know for how long the issue exists but old posts about crashes may be the same issue.
So don't lose time asking for a solution for crashes, it's a known bug now.
I'll miss this stack anyway, it has a good design, just needs to solve this. The dev did a good job but the project needs more attention from more devs now.