I will say directory work better in link building but not really work good for traffic generating except those high quality directory like DMOZ or yahoo directory
few top directories like yahoo, dmoz, botw will send you some traffic. aside form that, most of the individual directories usually dont have much visitors of their own so cant send you much. if you are looking for direct traffic, then directory submission would not be something that will be instantly helpful. you will get some backlinks form the submission which in turn will help but as far as goes to direct traffic, try something else.
Hi, there i am a blogger for 2 years, i personally think that commenting on other blogs, social bookmarking, youtube video submission and guest posting on other blogs are some of the quick and best way of traffic generation. Directories will only help you in link building and some time it cause serious problem in the form of duplicate contents as directories index your site or blog feed in its pages.