I downloaded the Beta so I could test out the Background Removal, as I am providing down to the pixel edits and am spending a ton of time removing or adding back in subject/background edges. The selection is no better than in Photoshop and when I went to submit a comment in the Beta PS, the comment menu showed up, but not the ability to write a comment or add a picture (and yes, I clicked those boxes). When I exited the comment window, I got a "successfully submitted" message - or something similar, when I hadn't been able to give my feedback.
I'm posting here the selection zoomed in to show how the background removal tool leaves holes in the subject and is not smooth which is the same as in PS.