I would love to, but I can't because that would imply that I had knowledge of POUND.
NGINX was chosen by me because I heard a lot of good things and the documentation for what I needed was easy to understand (I needed the ability to run multiple site behind one IP address, based on host name). From there on I explored more of it's capabilities (run static files from its own directory, act as a reverse proxy to shape traffic, act as a real load balancer, cache images on the harddisk) and with each single step the conf files grew a little bit but are still easy to understand.
Good things I heard: It is blazingly fast and does not harm the resources. It also doubles as an IMAP proxy and has FastCGI support built in. I can verify the blazingly fast. It serves 10 pages per second as a load balancer with cache on a Pentium 4 with 2GB of Ram and the load seldomly gets beyond 0.05, not to mention that pages come up much faster than with just one AOLserver.
