I've been using Apache 2.2 with mod_proxy_balancer to do load balancing for PHP and Rails apps for over a year now, and had pretty good experiences with it. Sin

I've been using Apache 2.2 with mod_proxy_balancer to do load balancing for PHP and Rails apps for over a year now, and had pretty good experiences with it. Since I support a lot of existing Apache servers, the configuration is easy for me to work with, and the ability to do authn/authz and SSL termination at the load balancer lets me keep the load down on my application servers. It's probably not as fast as Nginx, but I haven't found our load balancers to be a bottleneck. In fact, we've been doing load balancing on a pair of really, really wimpy servers (Celeron CPU and 512MB of RAM) running Apache on OpenBSD for about a half-dozen different apps for the last year, and never seen the average load climb up over about 0.5, even while handling upwards of 300 requests per second.