Google Contacts is a free, easy-to-use contact management tool that allows you to organize your contacts in a simple interface with fields and segmentation. It has native integrations to other Google products such as Google Calendar, Google Drive and Gmail.
With Apple's iCloud, you'll always have up-to-date versions of all your photos, notes, documents, contact lists, and more. The service keeps all your devices in sync, allowing you to share information between your computer and other mobile devices at home or office.
PieSync offers the only solution in the market to keep your customer data in sync two-ways and in real time, processing new entries as well as historical data. Your contacts are kept in sync automatically, so you don't need to worry about it once the configuration is set up.