Sun has released benchmark reports about Solaris' ZFS vs. Red Hat ext3:

Download the benchmark report here.

Sun claims for ZFS to be a revolutionary file system, and proves it by their well-documented, and objective (but not really) benchmark report, found at the link above.

ZFS has pretty much overall gain, when compared to ext3, which was to be expected. Of course, what Sun conveniently did not mention, was the alternative of filesystems on RH (or any other linux for that matter).
Are we really impressed about ZFS outperforming ext3? I for one am not, and most sysadmins know that ext3 is not the most performant filesystem in existence. If Sun really wants to show off, they would've taken benchmarks of other filesystems as well, though I'm sure there's a pretty good reason why they haven't done so...

Sorry, Sun, but you have to do better than that.