I usually prefer Facebook because it is easy to use and also free. Facebook enables you to reach many people at a time, promote your product and you can also create links which interested parties can use to get to your main website or site.
I think facebook is the best... 1.4 billion+ monthly active users cant go wrong.. Also don't forget to make a twitter for micro updates.
I believe they are both the same because they are both just another place where people may be that can be interested in what you are up to. Maybe how you can help get others certain kind of information they would like to learn more about. Facebook and Twitter are best for some but usually never works the same for somebody else because two people have so much of a difference in their business that for business, it's best to find out which traffic source is the best for a certain person. Only after finding what converts or what works for doing what you enjoy to change peoples lives, that traffic source should be a place to expand and build out until it's no longer worth the time, if ever. Search engines, social sites, keywords, forums or websites are more traffic sources that can be better but who knows. The research has to be done first to find out which is best. I don't believe anybody can go on what is working for somebody else. Not in todays world. Most bigger social sites in most niches are already dominated by people that have done the research and built them out over time. They dominate. All successful people in this crowded online environment have done the research and the few that are willing to take that on will all be the next wave of people that dominate the hidden sites that work like Facebook and Twitter in the years to come. But yea, Facebook and Twitter are just more social sites to sell training for with few results.
IT varies vastly. Since our business is a magazine, different content works on different platforms. Some work well on Facebook, some on Twitter. Google Plus helps a lot in positioning our articles on the Search Index.