When anchoring don't you want to know how much rode you releasing. And with some models, like the AA500 series, you can even preset the amount of rode you want to release and off it goes. Everyone that I have spoken to has said that it has made life so much easier and that the AutoAnchor is up there with GPS.
Looks like one of the simplest devices. If you have some spare time you can build one - just need an optical sensor. Mount it on an axle at winch, measure how long distance one rotation is on the chain. Plug the sensor in the PC. And in some software count the ticks. A relatively simple script would do it. Then interact this script with the GUI you are using. Simple, but you need your hands to grow from the right places