Not free, but Fastmail supports custom domains, is very fast, and now has calendars with CalDAV: http://blog.fastmail.fm/2014/01/23/calendar-now-available-on-b

Not free, but Fastmail supports custom domains, is very fast, and now has calendars with CalDAV: http://blog.fastmail.fm/2014/01/23/calendar-now-available-on-beta-fastmail-fm-for-testing/ http://blog.fastmail.fm/2014/01/23/calendar-now-available-on... Unfortunately, CardDAV is not yet supported for address books, but apparently they are working on it. The advantage of paying is: no ads, no data mining, no privacy problems :).