electric gyro options

Our club is considering installing an electric AI as a backup after a
vacuum gyro failure not involving the suction system. We have three
cherokees and are looking at three alternatives (we'd like the same one
in all the aircraft):

http://www.lifesavergyro.com/purchasing_home.html

http://www.sportys.com/acb/showdetl....roduct_id=7439
(ignore the request for password)

http://www.gyrohouse.com/catalog/items/item551.html

The first is a $4000 unit, the other two are less than half that.
Anybody out there have any experience with these units, or the companies
that make them?

Jose
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