Cyrus Imap - Postfix - lmtp or pipe ? And why ?

[Bryntez]

Hi list..

It's about Cyrus Imap and the postfix delivery mechanism...

I have read earlier in this list that it is better to use "lmtp"
as delivery than "pipe". We are using the "pipe" option 
in postfix since we installed Cyrus Imap 2.1.5 and Postfix on 
our Redhat 7.3 system earlier this year. (because the howto was
specifying us to do so...)

I havn't noticed any hazzle....

So my question is: Why is lmtp better to use than pipe ?
Is it speed, more stable, security or what.... 

Regards
bryntez