I guess all of it needs to be taken with a grain of salt. But then again, if one has learned exactly how to read these things, they most probably will get accurate results.
Like the astrolabe thing.... I don't know who wrote the descriptions but I don't agree with some of the ones based on the planetary positions. Any astrologer (or good book on astrology actually) will also tell you that what the planets tell is no where near as important as ones sun sign. Ones sun sign characteristics are the biggest influence, then the Moon and Rising. The planets describe different aspects of ones life. Also, the descriptions (I'm quite sure), are not different for each degree that the planet is in, and in actuality it can make a difference. Here's something else that many people don't think of: Was the birth premature? Was it a few days late? That can make a significant difference in the reading as well.
Oh well... just my view... who knows....
The astrolabe thing is pretty good though, especially since it's free. =)