Approve / Deny works for me, as does going back to the original version.
I am certainly not a UI expert, but in regard to a positive outcome (like a new user), I believe the first of two options should be to accept that positive, not deny it.
I just went through six new users before making this post and it felt very unnatural to have to answer ‘No’ to allow them on to the site.
Once I realised the change was in effect, I went back through the admin logs to check I hadn’t accidentally denied users because it was so counter-intuitive.