Will the direct access accommodate Apple (iPad) or, are we still using 3rd party apps like Citrix receiver?
To my knowledge, DirectAccess is only supported by Windows clients, and Microsoft has not announced plans to support any other OSes. If you need an iPad or other device to have access to your corporate network you will have to rely on a VPN tunnel. The only true advantage of DirectAccess is that it is invisible to the end user. VPN tunnels are invisible after you log in, so you are really just saving a user the effort of logging in.
Hope that helps,