Byte.com has a column by Moshe Bar benchmarking Linux and FreeBSD in several areas. "Overall, I believe we have now reached a very stable and well-performing Linux.
Needless to say, FreeBSD is as stable and fast (or faster) as ever. The 2.4 Linux kernel
has grown out of its early problems and there is no reason anymore to hold on to the old
2.2 kernels, especially on new servers. The TCP/IP subsystem (with zero-copy and
other very important features) takes the last out of your Linux server. "
November 14, 2001