I've no idea what the architecture is like, but being Ada, I'm pretty hopeful it delivers some nice guarantees (or at least hefty promises) regarding reliability.
An outdated, probably flawed (aren't they all) benchmark:
http://wiki.ada-dk.org/aws_vs_node.js
If nothing else it seems to indicate that aws isn't hopelessly slow.
There's also awa - the Ada web framework. I've yet to play with it, but it would appear to be relevant:
http://code.google.com/p/ada-awa/
According to a stack overflow answer[s], Ada also comes with a spitbol-package, allowing you to use spitbol/snobol rather than regexpes for pattern matching. See eg the bottom of:
