HAProxy supports sophisticated balancing schemes, rule-based backend selection, etc. I.e., if Host header is X, and Ip is Y, but no cookie was provided, then u

HAProxy supports sophisticated balancing schemes, rule-based backend selection, etc. I.e., if Host header is X, and Ip is Y, but no cookie was provided, then use pool... with this balancing scheme. nginx's proxy setup out of the box is useful, but I wouldn't consider it on par with things like ZXTM or a Big IP when it comes to robust balancing/fallback patterns and flexible routing rules. If there's a module that provides all that, I'm happy to hear about it--I haven't found it yet.