The share shows more information such as listing title,link and stands out more on Facebook. Like just shows a title. I could add a like link as well but the share system shows more data.
That's not true, the share feature and the like in facebook, is the same now (and the share button was been deprecated by facebook)... And people click more on the like button than the share... just saying.
Probably not every one is seeing the full like feature, but it show the title, the image and the description, if it is well implemented