To illustrate the benefits of the different approach we compare mass-autocomplete with the popular angular-ui typehead. We use the amount of watches and the total time the app spent digesting as measures.

Our main goal is to keep the number of digest execution to a minimum and to make them as fast as possible. To reduce the amount of digest executions we first need to make sure it's triggered only when truly necessary. To reduce the digest time we want to make sure the evaluated expressions are simple and fast, and keep the watch count to a minimum.