They have equal content, and the wiki does not say otherwise. I should know, I wrote that page lol.
You can load a save from before the choice. If it helps, there is an autosaves page to the left of the first save page.
The wiki lists 9 events on both routes.
Since you specified sex scenes, yes, Slave Route focuses more on treating slaves as sex objects rather than people, thus it has more sexual content than standard content.
You don't get the same events on both routes because it is a choice - treat them as a person, or as an object.
If you want to see both routes' content, simply make a save before the choice :)