Without wanting to gerleanise that all directory submission services are to be avoided as I am sure that there are some that are good value for money, personaly I would prefer to list any directory submission myself so that I know my store description and or product descriptions on each directory site are how I want them and differ slightly each time.I would also want to know exactly where, and on what sort of directory my site is being listed on to ensure that it isn't placed on some spammy directory that could possibly do my site more harm than good.