there are software that you can use, however it is prone for being banned because of spamming reasons.. you can do it manually but that will take time..
There is doubt that facebook is better than the twitter as there are lots of users who are using facebook for chatting with friends, sharing photos, video and many more. Also for the business purpose Facebook is better option for the promotion of site or products.
Depends on your strategic approach... you need people actually VISITING and view and giving comments then Facebook.. and its comparatively popular...
Both are excellent marketing mediums, it just depends on your target market(s). I think sharing content on both at the same time (e.g. via Hootsuite) is your best bet. I hope this info helps.
ha ha ha its face book because it has a great user interface also its always update its self so face book is better then others