Security Portals

I was hoping to get an objective opinion about a security safeguard that I have been hearing a lot about lately - security portals. Several banks in the PA/NY area have invested in them, and have said that the deterrence factor gained by these devices is enormous. I have gone to one bank in particular that has one of these systems installed, and I have to say, they are quite impressive. I was told by the President that some of the models offered by the manufacturer even offer explosive detection. He also said that he was mostly attracted to the portal because of its transparency to the customer. He said that there is currently only one manufacturer that he is aware of that is getting a lot of attention in the banking industry with these patented devices, and I was hoping to get an expert opinion on them before I move forward with a recommendation to a client of mine.