I presume that MarketPress users are the same as regular users or members from the membership plugin.
But is it possible for the login redirect to be to something on the front page rather than the wp-admin back page as used by admin?
Is there a recommended plugin that will enable this? I don't think the login redirect is appropriate. What is needed IMHO is a login box on the front page that, if a user is an administrator etc, opens the dashboard otherwise if a user is an ordinary user or member at whatever level from the membership plugin, acts appropriately. In the MarketPress context this probably means pre-filling the checkout details.