I've happily used Horde for well over 5 years. I was really really looking forward to Horde4. Once it came out, I immediately tried it. Tried to install it, that is. I failed. The lack of clear documentation combined with the dark magic of php-pear kept me from migrating. And even when I did get it installed I was unable to comprehend the UI. It completely changes depending on what 'application' you're using. There is no consistency.
E.g.: The calendar in Horde4. The interface completely changes into nothing you've ever experienced. It's unrecognisable from the rest of Horde4.
I migrated to RoundCube + Plugins for calendar (caldav+davical) and addressbooks (carddav + davical) and have been a happy, android syncing camper ever since.
php-pear dark magic is nothing compared to installing the framework libraries from git! The pear.horde.org instructions fail to mention that you must install horde/Horde_Role before any of the applications.
The UI is currently undergoing a rewrite, but the default interface can be forced into the traditional view in the Horde configuration.
