Review on Squid-Cache by David Hill

I love that it works well with subdomains without having to rewrite code or setup additional vhosts/servers as we need more sites served from our servers in order of importance (eg most traffic first). The fact you can configure your site's cache timeout separately gives me an advantage over other products where they are all set at some default value - which isn't always appropriate! We have multiple companies using this web service so if one goes down another takes its place when needed. This way no downtime will be experienced while switching out content providers like Google Apps etc..