Dan:

I don't personally have one but have seen and listened to some at our field. They can have 'static' w/certain fuselage types/locations until best placement is found. Can tell when you are in the lightest of lift. Is especially helpfuly when you are specked out or higher altitudes and cannot tell for sure if you are going up or whatever. It does give others a very good frame of reference if you know a certain sailplane is at 600 meters and you can compare your flight with his. Also the battery monitor can be very valuable. As to the cost, everyone has to make up their own mind to determine if it is worth their hard earned bucks or not. Good Luck.

Gene