Your results depends on many factors, however there is no reason why you should not have the same good results with an autosubmitter compare to manual. Chameleon Submitter (
www.chameleonsubmitter.com) will take care about all the site rules so you will know that you are sending the right galleries in right format to the right places. It saves time which is a bonus so you can concentrate on the other stuff..
Autosubmitter is a choice of many people these days. Chameleon has a fair database that updates on a daily basis, all sites are set up according to their individual site rules.. its clean, fast, and very user friendly - as for your question regarding to how much time you will need to learn it, I think average user will only need a few days to get fully comfortable with it.
Check out these official and interactive Tutorials, there you can see how to work with this tool properly, how does the software actually look like inside and how to get the maximum out of it:
http://www.chameleonsubmitter.com/tutorials.php