If your expecting 1000+ hits then the best thing to do will be to download them both and see which one wins. From my experience the time spent isn't really in the servlet container anyways.
If in doubt though, jetty is the one to go with.
For Jetty, you will get best results if you build from CVS, as I have recently refreshed this with the latest and greatest - Jetty-4.2.4. This has been thoroughly optimised over the Jetty-4.1 series, which will be in your 3.0.x release.
If CVS is not your scene, let me know and I will mail you a copy of the latest .SAR to play with.