I looked at SmartOffice, totally awesome product, but a bit cumbersome for my primary P&C business. It doesn't have a built in automatic autoresponder, but I believe it has a way to send emails to the client on a status change, so it has close to the same thing, just a manual autoresponder
There is a fine line between staying in touch and spamming a lead. My feeling is if the client sees it as informational, as in you define some terms, some things to watch for, etc, it both helps them see value in the piece, and raises thier opinion of you.
Dan