[CentOS] unison versus rsync

>Put them here:
>http://rpms.linuxpowered.net/hpn-ssh/
>
>All the usual disclaimers apply, I have these running on a few
>dozen systems at different data centers running file transfers
>24/7 for the past year now that I think about it.

Nate,
That's great! I am not convinced yet that an rsync daemon will suit my needs
from the authentication standpoint. That being said, from the windows side I
have to figure out how to get hpn-ssh in windows to do simple rsync/ssh w/o
encryption. The only CopSSH implementation I have found is based on OpenSSH_4.1p1-hpn
OpenSSL 0.9.8 05 Jul 2005...

For the sake of being ready Saturday, what is the most secure (not using ssh) to
authenticate in a script with an rsync daemon? Looks like it only does the user:pass
pairs (not really good for script) or host based wrapper style security?

Thanks everyone!
jlc