From a StackShare Community member: "We are a LAMP shop currently focused on improving web performance for our customers. We have made many front-end optimizations and now we are considering replacing Apache with nginx. I was wondering if others saw a noticeable performance gain or any other benefits by switching."
I use nginx because it is very light weight. Where Apache tries to include everything in the web server, nginx opts to have external programs/facilities take care of that so the web server can focus on efficiently serving web pages. While this can seem inefficient, it limits the number of new bugs found in the web server, which is the element that faces the client most directly.