automatic submissions are where... you give the website information to a software tool and software does the submission - problem in these types of submissions are most directories ignore these types of submission manual submissions on the other hand as the name suggests are done by human hand - and its highly acceptable as there are no software (bots) involved... hope this helps... (if you want any kind of submission do let me know)
I prefer manual submission with a form filler, done by myself, im not knocking automatic though, i bet theres some pretty decent services out there. I just like the flexibility with manual. To date i think humans still choose categories better than software. on second thought, not all humans, but you know what i mean.
Iv been using a directory submit tool digixmas myself, its semi automatic. It uses a form filler and lets YOU chose the proper categories. I think it works very well. http://www.digixmas.com/
Automatic VS Manual directory submission from my point of view they are both the same if done in small amounts over a long time. i use Automatic and i set it to run over 5 days. a big thing with Automatic VS Manual directory submission is that alot of dirs dont approve links if placed in the wrong category. i dont bother with directory submission on smaller sites as i rather have my links home grown i let google deal with my links i find some time you can have to many directory submissions.
Manual Directory submissions are way better as you can customize the information of your website in each directory. You don't want all the directories to have the same description of your website all over. It won't help your SEO rankings. Good luck
You can make your own list, there have a good guide on the help menu at top. Or go to their support forum to find lists of thousands. I got 2.5k within about ten minutes lol.
I have auto submissions almost every day. Poor description, not proper category. So that's right I am removing from directory. Hint: Russian spammers love it auto submission.
Never use automatic directory submission tool or any services, I only trust myself for selecting quality and Seo friendly directories.