We understand it's important to trust the product that's going to handle important data such as your contacts. You don't have to take our word for it, you can read what our customers are saying about PieSync. Customer reviews can be found here:
Are you also a Happy Syncer :) ? Don't hesitate to leave you're own review behind. If you run into any questions, give us a shout via firstname.lastname@example.org! Happy to help!