Let's get a few things out of the way first:

1. No, I didn't go through it.
2. I will continue to refer to TSA's machine as a nude-o-scope, but will use WBI for the AMS equipment, for reasons described below.
3. This is one sample. YMMV.

I returned last week from Amsterdam (SYD-SIN-AMS and return) and was able to observe the WBI setup at Schiphol.

Most people know that AMS has security at each gate rather than centrally. While walking from my arrival gate, (E gates) it looked like some gates had two WTMDs while others had two WBIs. (Hard to tell, though.)

My departure gate had one WTMD and one WBI. There were US-bound flights from that gate later in the day, so it seems likely that the following may apply to US-bound passengers. Points of interest:

• A single line led to a document checker and then split to the two machines.
• There was no one to direct people to either the WBI or the WTMD; people just chose whichever line they wanted. ^ I guess.
• There was a professionally printed brochure available in a rack on a counter just before the document checker. (It was the one available here.) ^
• But you had to take two steps sideways out of line to reach it.
• There were no other measures to inform people about the WBI.
• BUT the display is on the back of the unit and is the cartoon figure, not a real body image. ^^
• By all appearances, the screener running the WBI views that cartoon figure and clears the passenger. She did not appear to be wearing a radio or have other means of communicating with a remote viewing station. Furthermore the number of gates at Schiphol would make remote viewing for all WBIs a logistical nightmare. So while I'm as suspicious as anyone, I believe that they really are just using the cartoon image. ^^^
• The setup for the checkpoint mitigates against theft while being scanned. The x-ray machines are on the far left and far right, while the WBI and WTMD are next to each other in the middle. So the only people passing the x-ray output area are the passengers that go through the corresponding scanner (WBI or WTMD). Furthermore, the only place for a potential thief to go is into the boarding area for that one flight. ^^
• Shoes did not have to be removed. ^
• They're using MMW, not x-ray. ^
• My colleague (who arrived later and is of the "I don't care myself but people should have a choice" school) went through the WBI and said it was much slower than WTMD.

And the sheer cost of this is breathtaking. There must be more than 100 gates at Schiphol, each requiring 1 or 2 WBIs at $170,000 each.

Bonus: Despite being an ebil metal-hip terrist (as goalie would say), I didn't set off the WTMD so I don't know if I would have been WBI-ed or gotten a patdown. I watched the process after I was through and didn't see anyone getting sent back to go through the WBI. In fact, the checkpoint was quiet and polite. No barking. No attitude. No authoritay.

In summary, if you absolutely, positively must have the WBI, the implementation at AMS is as close to passenger-friendly as possible. The only downside is that it's slow.