I am most familiar with RHEL/Fedora and I commonly use autofs with direct maps to mount NFS servers. Direct maps are not well supported in autofs4 but work great with autofs5. In fact on RHEL 4 and Debian Lenny/testing which both ship with autofs4 you have to manually enable direct maps in either /etc/sysconfig/autofs or /etc/default/autofs configuration files.
I'm used to using autofs5 in RHEL 5 and newer Fedora versions but as it turns out autofs5 is not included in Debian Lenny/testing which I'm trying out at home. One of the issues I ran into with autofs4 is that you can't mount the key directly under the root filesystem. You have to make the key under some other directory first. This behavior is described really well in this bug report against autofs4 on Fedora Core 3 https://bugzilla.redhat.com/show_bug.cgi?id=145533
Anyway if you want to get around that issue on Debian Lenny/testing it's easy to just install autofs5 from the unstable branch this way:
# aptitude install autofs5/unstable
That command/syntax is explained on this page, section 6.2.6:
You don't have to do this anymore. Debian Lenny stable still seems to include autofs4 by default though. On Debian Lenny which is now stable just do 'aptitude install autofs5'