Hi, I think, as most, is always better to proceed with manual submission, choose a list of 10-20 good directory and then with patience submit to everyone your site and then wait for the inclusion. some good are: dmoz - mastermoz - jayde - botw etc etc bye
I'd avoid any directories that are blatantly only for seo purposes - i.e. submit to directories that are used by people. These are likely to be of higher quality and better structure.
Submit directories allow you to get quality backlink, create awareness and get traffic . Your website or blog maybe a optional of reader searching for. You can get lot of traffic there and the link juice is high. It help in SEO alot. But mostly submit directory do need link exchange . So try to find for one way backlink.