While I absolutely refuse to go through a backscatter ATI because of exposure to ionizing radiation, I have no problems going through the MMW, and in all my trips through the MMW, I have never had an after ATI pat down, I make sure there is nothing in my pockets, including lint that might show up as an anomaly.
My last time I went through the MMW, in TPA it had the new gumby software, so I was able to see what the MMW had picked up, there were 2 small red boxes on the image and the screener said there was no problem with what he saw and cleared me. I even asked him if the red boxes indicated something and he said no, so I thanked him and went my merry way.
Are both useless and a waste of money, absolutely
Mr. Elliott