Perhaps the text could be added either side of the grab handle to clearly illustrate when you are seeing more of the before or after image as the slider moves.
I personally rather would prefer the editable text on the upper respectively lower image corners to not to obstruct the images.
But there also should be a function of no text. I am using right now the bric not for a comparison but for to demonstrate just 2 different location views and text would be wrong in this specific case.