No we aren't ogres (at least I tell myself that), but we have worked with no less than five nannies in the last 12 years and Careworks, although expensive, has been terrific. The remarkable thing is that all have been great people and we keep in touch with each one to this day which is pretty amazing when you think about.
Linda really cares about finding the right person that fits you. You and your significant other take both a personality and a parenting test and so does each nanny she has prescreened.
The test itself taught me more about what it would be like to be a parent and how different folks are that I would have ever though (example, if your son is arrested for shoplifting, would you blame yourself, rush to him right away,....). Not the thing you want an anxious first time dad to answer :-)
In any case, it means that you have more to go on than just is the person nice. A nanny spends hours and hours with your kids, so it is nice to know their styles are the same.