Reporting Services Tool Tips

What has your experience been with using tool tips in Reporting Services reports?  This feature gets some mixed reviews.  I see it work and I see it, well, not work so well at times and under certain conditions.   …but I’m interested in your unbiased feedback.  If you’ve used this feature and you have something to say about it, please post a comment.  I’d like to start a dialog.  I have some thoughts and experience with this but I’d like to know what others think, first.  Oh, and by the way, members of the Reporting Services product development team may be listening.