I am a big fan of the Attribute Assistant. I agree with a previous poster that the documentation could be beefed up a bit especially with the EXPRESSION method.
It took me a while to figure out how to configure the add in but once I did I started using it in most of my data entry workflows. I wouldn't say I am pushing any envelopes with it but I have saved hours of typing and stopped numerable errors from getting into my layers.
I primarily use GENERATE_ID, TIMESTAMP, CURRENT_USER, NEAREST_FEATURE, LAST_VALUE and PROMPT. Best add-in to come out of Esri.
Jeff Ward
Summit County, Utah