My experience is that they were very discrete and careful.

They are very discreet, but the problem i have had with them is that they are not very efficient in getting back to providers, and therefore not terribly useful.  I have contacted them to verify a potential client a couple of occasions, and they either never got back to me, or it took longer than was practically applicable.  In my experience, I am not sure it's worth the investment.

The question is how do they safeguard the information, and what happens if their records fall in the wrong hands?