[Zope] Network Appliances NetCache vs. Squid

My host has offered me to try accelerating a busy zope-based site using a Network Appliances NetCache. He kept the device from a customer which went bankrupt. Neither of us has any experience with the device. If anybody can share some insights in regard to Zope and how this compares in use something like Squid as a reverse proxy, I'd be most thankful. On that note, what are the issues of running squid on the same machine as the Zope instance to be cached? Are substantial gains only achieved if Squid sits on its own box? Cheers Marc