postfix / maildir / nfs -- and good nfs implementations

[J.P. Trosclair]

I've got a couple of questions about using maildir on top of nfs in a HA 
setup.

1. What are the chances of duplicate file names when running multiple 
instances of postfix delivering in maildir format to the same location?

2. "That said, Postfix will in many cases work very well on NFS, because 
Postfix implements a number of workarounds (see below). Good NFS 
implementations seldom if ever give problems with Postfix, so Wietse 
recommends that you spend your money wisely."

Could someone provide information on success utilizing particular NFS 
implementations in their setups? I've used NFS more than once but I 
honestly have no idea if the systems I've used it on would be good 
candidates alongside postfix.

Thanks