Which Database backend to use?

[Christopher S. Pallone]

I have noticed a couple of threads recently about the use of different 
database backends with cyrus IMAPd. Can anyone explain when and where a 
specific DB backend should and shouldn't be  be used? Are the current 
default values found in configure.in still considered the best options for 
most installations?

The current defaults for 2.1.12 are set to the following:
duplicate delivery database:    db3_nosync
mailbox list database:          db3
seen state database:            flat
subscriptions list database:    flat
TLS cache database:             db3_nosync
When should I consider switching to the skiplist backend?

Thanks for the help,
Christopher S. Pallone
Michaels Stores, Inc.