1. Storage and Hosting: OneDrive is a cloud storage service provided by Microsoft that offers online storage for a wide range of file types, while ownCloud is a self-hosted cloud storage solution where users have more control over their data and can choose where it is hosted.
2. Data Security: OneDrive encrypts data at rest and in transit, and provides secure access controls, while ownCloud allows users to have full control over encryption methods, data ownership, and security protocols, providing a higher level of data security.
3. Customization and Features: OneDrive offers a set of predetermined features and limited customization options, while ownCloud can be customized extensively to meet specific user requirements, with the ability to add or create new features.
4. Collaboration: OneDrive is more suited for individual use and basic collaboration features, whereas ownCloud allows for greater collaborative capabilities among multiple users, with the ability to share files, work on documents together, and manage permissions within the platform.
5. Cost and Licensing: OneDrive is a subscription-based service with tiered pricing plans, while ownCloud is open-source software that can be self-hosted for free, with optional paid support and enterprise features available.
6. Integration and Compatibility: OneDrive integrates seamlessly with other Microsoft products and services, such as Office 365 and Outlook, while ownCloud offers compatibility with a wide range of third-party applications and services through its app store.

In Summary, The key differences between OneDrive and ownCloud lie in their storage and hosting methods, data security levels, customization options, collaboration capabilities, cost structures, and integration possibilities.