third parties yoin my scores...

[Chris Stark]

How is Rackspace not reliable enough? Where their servers/data connections going down or was it the setup? I've been there on the sys admin side, managing your own servers for high traffic sites is tough. How do you have your server setup now? You're using NginX as your web server? Memcache? Varnish? Apache?

The benefits of prefetching is great (potentially a second or more) for some and the downsides are very little (extra couple bytes of HTML code). Sometimes you have to look beyond benchmark testing and look at real world usage.

Cloudfront is a dog, AWS calls it a CDN but it really isn't. You might want to look at MaxCDN, NetDNA, or Rackspace Cloudfiles (which use Akamai).

In addition to a better CDN you should also take a look at Cloudflare.com, I run almost every site I operate through it. Some of it's biggest users are companies like Stumbleupon.com