Up until quite recently I've always recommend that if you're an Android mobile user who needs access to your email, calendar and contacts, the best method was to use
IMAP to synchronise your email and
ActiveSync for the calendar and contacts. This two account approach works well but I've always been aware it could be simpler to set up.
Thankfully, ActiveSync 'push' email was added to
MDaemon in version 12, so you're now able to enjoy full synchronisation of both your email accounts, calendar and contacts with just a single ActiveSync account.