Password Sync VS ADFS

Access Method	ADFS	DirSync w/ Password	Verdict
Outlook 2010/2013	Prompted for credentials on first connection (and at each password change) with checkbox to remember them.	Prompted for credentials on first connection (and at each password change) with checkbox to remember them.	Draw, both have the same experience
ActiveSync, POP, IMAP	Prompted for credentials on first connection (and at each password change) with checkbox to remember them.	Prompted for credentials on first connection (and at each password change) with checkbox to remember them.	Draw, both have the same experience
MS Online Portal, SharePoint Online, Office Web Apps	Internal: Pop up offers click to sign in with no credentials required (External Forms Based Prompted)	Prompted for credentials on first connection (and at each password change) with checkbox to remember them	Better experience for ADFS while internal to company network, draw when external
OWA	Internal: Seamless (External Forms Based Prompted)	Prompted for credentials on first connection (and at each password change) with checkbox to remember them	Better experience for ADFS while internal to company network, draw when external
Lync 2010/2013	Seamless (with Sign on Assistance installed for Lync 2010)	Prompted for credentials on first connection (and at each password change) with checkbox to remember them.	Better experience for ADFS

    SSO Using ADFS

Pros	Cons
True SSO with minimum credential prompts	Additional infrastructure needed to deploy FS and Proxy FS
Better security than when using DirSync’s password Sync	Added point of failure (even if multiple FS servers are deployed, this option brings in more dependencies for the setup to work)
	Additional cost involved with this setup
	SSL certificate from a public CA is needed and needs to be renewed on a periodic basis (cost/administrative work involved)
	More time/effort involved in setting up

  DirSync with Password Sync Pros and cons above reversed 🙂 In addition, based on my experience, for DirSync with Password Synchronization, you enable your users to use the same password they are using to logon to your on-premises Active Directory to logon to Windows Azure Active Directory. The users’ accounts and password are authenticated by Office 365, but for SSO with ADFS, the credentials are authenticated by the on premise ADFS server.