Visiting Berlin last year and taking in every tour available I found it a fascinating city. I asked a few people about the STASSI and how they managed to melt away without meeting too much in the way of their role in the repressive eastern section.
The only two people I met who were willing to talk about the STASSI were two students who were very angry that these people were now in the best jobs, they told me there were very few taken in to account for their activities, they hinted at the"let sleeping dogs lie" alternitive, in their opinion, wrongly pursued by the authorities.

I would recommend Berlin to anyone contemplating a visit, a city for every taste.