How safe is it to use AP?

I am a student with my I-485 pending. (I came as F-1 and filed I-485 as a dependent. My wife’s I-140 has been approved.) I plan to use AP to go back China this April for about 30 days. I would like to know:

1) how safe it is to use AP? Is there any chance I could be denied for entering?
2) What is the procedure I should follow to use AP to come back? What are the documents I should take with me?

Thank you so much for your information!!