[Dovecot] Dovecot 1.x vs 2.x

Hi All,

I'm currently in the planning stages for a technology refresh for a very large mail installation, and looking at using Dovecot with LDA/Sieve/FTS_Solr and a number of other plugins to give our users some great features. Currently, our standard distribution is Ubuntu Lucid, which has Dovecot 1.x included with it in pre-built packages, and Dovecot 2.x is in the upcoming Oneiric beta coming out next month.

My question is, are there any compelling reasons why we should gravitate towards running Dovecot 2.x beyond the fact it's the "latest and greatest" version? What features would we miss that we're likely to want or need on a very large installation (i'm talking dozens of VM's, over 1 million mailboxes).

Thanks