I cannot say FreeBSD better then any Linux (RH,mandrake,etc) or any OSes cause I am still learning and I am not expert yet, but I am learning fast .( I guessed )
For me every OSes it's good whatever Os you have... you need to learn , howto secure,etc and stick with it and fortunately I like FreeBSD and Linux.
A few things I like from FreeBSD ;
1) Their ports system (including portupgrade )
The advantage of a FreeBSD ports package over Linux when installing package is what I have to do is:
Lets say I wanna install ddos tool (this tool to check maybe I have DDOS attack)
# cd /usr/ports/security/find_ddos <<<<< just example
# make install clean
and everything would be taken care of( you don't have to find dependencies ..like you do in Linux except Gentoo and Debian, BTW on Linux you can do like this ( install package) for Gentoo Linux using Portage and Debian Linux using apt ( I am not really sure about debian, never used debian))

And to run it I just logged as root and do like this:

# /usr/local/sbin/find_ddos
Running with the following default options:
/usr/local/sbin/find_ddos -g files -l LOG -p /tmp /

This material and tool is furnished on an "as is" basis. There are no
warranties of any kind, either expressed or implied as to any matter
including, but not limited to, warranty of fitness for a particular purpose
or merchantability, exclusivity or results obtained from use of the
material. There is no warranty of any kind with respect to freedom from
patent, trademark, or copyright infringement.

If the program "find_ddos" generates a log file revealing unlawful access
of a tested system, system administrators are encouraged to contact their
local FBI field office or the NIPC.

Please review the README file before continuing.

Do you accept these terms? yes

In the future, you can run this tool with the "-y" option from the
command line to acknowledge these terms

Logging output to: LOG
WARNING: Unable to scan running processes.
This will happen if the /proc directory is not a procfs.

Scanning "/tmp"...
Scanning "/"...

No DDOS tools found.
#



2) Merged virtual memory and filesystem buffer cach
3) Security
4) cvs

5) FreeBSD is far more stable and tested. It has been around for MUCH longer and has
a very nice, solid foundation. It is a superior server because the FreeBSD core team
holds stability above all else, and all additions done are added with stability in
mind.

6) FreeBSD can run most Linux software just fine. Anything that is NOT statically
linked should work like a charm.

7) FreeBSD's code is very clean, consistant, and professional looking.


8) FreeBSD is more integrated. FreeBSD is an OS, whereas Linux is just a kernel.
There is only one FreeBSD, and a million Linux distros.

9) FreeBSD is well tested in enterprise server environments.

10) FreeBSD is built democratically, with a core team of several people
making the decisions.

11) FreeBSD is generally more secure. It has features such as the ability to run
multiple copies of itself on the same PC, all isolated from each-other, so as to
prevent the compromise of one service leading to a full system compromise. It has
also supported certain extended attributes, officially, for years, such as the
ability to make a file undeleteable even by root, the ability to make firewall rules
unchangeable even by root, etc. (in order to change them, you have to boot to single
user mode as root, so remote compromises are all but impossible)


Cheers


















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