I remember Maatt Cutts from Google saying that links from directories are given weight as long as they publish the links on merit - that there is some quality control. If they just accept any link then Google cannot read from an inclusion that it is a vote of quality. So if the directory is not litterd with dodgy sites such as porn and viagra, then you should get some value out of the link.
Directory Submission can get you good traffic from Search engine. It helps as it offers Backlinks. Before Submission verify about the Dir. submission website 1) Must have Good PR and Alexa 2) Must not have too many ads (looks spammy) 3) Good, if crawled frequently by Search engine 4) Better, if has a section dedicated to the niche of your site
what you can do to verify if a directory is indexed and well optimized is: type in Google search "site:directoryurl" (replace "directoryurl" with the directory url) and check if resultst have different link title and adequate description. If not its useless.