Dex is praised for its effectiveness as a personal CRM, particularly for professional use. Users appreciate its ability to prevent contacts from "slipping through the cracks" by organizing interactions and setting reminders. The importing system and synchronization features are highlighted as time-saving, with the browser extension allowing easy addition of contacts from LinkedIn or Twitter. While some users report issues with speed and bugs, the overall sentiment is positive, with many finding Dex superior to other CRMs like Clay.