[jspaw]

It's multithreaded, so can take advantage of more CPU mores, unlike squid.

It has total disk cache persistence, so it won't lose any cache if the server crashes, traffic server crashes, unlike varnish.

If you've got cache spread over multiple spindles and one of the spindles dies while in production, it'll just keep on going, skipping that spindle. Squid does this, varnish does not.

It does run on linux. Actually it's what it was built on, originally, IIRC.

I have used TrafficServer (at Yahoo) and I'm willing to bet that it will overtake both squid and varnish as time goes on.