What the TSA people saw on the monitor was a mono-color human silhouette, with little squares of another color indicating the general area of where the questionable items were on my person.
I was asked if I had anything on my person, and I was patted down just in those areas identified on the monitor. My hands were also swabbed for a particle detector. After that, I was allowed to move on.
Overall, I think the machines worked fine. And while the $90 million spent on machines is a lot of cash, that money went to pay people who did good work in manufacturing the machines, assembling parts, writing code, provided maintenance of the buildings they were built in and so on. It wasn't just thrown out the window. That money went to working individuals who will pay taxes on that money who will give the government an opportunity to pay off the national debt. Furthermore, if those $90 million machines prevent just one terrorist plot that may not have been picked up by the previous generation of detectors, then it will have paid for itself multiple times over.
IMHO, not perfect but good enough.