1. Delivery capabilities: OneSignal and Pusher provide push notification services, but there is a difference in their delivery capabilities. OneSignal offers highly scalable delivery infrastructure, allowing the delivery of push notifications to a large number of devices simultaneously. In contrast, Pusher focuses more on real-time communication and event-based notifications, which may cause limitations in delivery capabilities for large-scale push notification campaigns.

2. Advanced targeting options: OneSignal stands out with its advanced targeting options. It provides granular targeting criteria based on user attributes such as location, language, preferences, and custom segments. This allows for highly personalized and targeted push notifications, ensuring that the right message reaches the right audience. Pusher, on the other hand, does not offer as extensive targeting options, leading to a less precise and personalized messaging experience.

3. Rich media support: OneSignal offers rich media support, allowing the inclusion of images, videos, and interactive buttons in push notifications. This enables developers to create visually appealing and engaging notifications that can drive user interaction and improve conversion rates. Pusher, however, does not provide native support for rich media in push notifications, limiting the design and interactive possibilities.

4. In-app messaging capabilities: OneSignal offers in-app messaging capabilities, allowing the delivery of messages and promotions directly within the app. This provides a seamless user experience and enables real-time interaction with users. Pusher does not offer in-app messaging functionalities, which might lead to a fragmented user experience when trying to deliver in-app messages alongside push notifications.

5. Pricing model: OneSignal follows a freemium pricing model, offering a generous free tier with basic features and options to upgrade for additional features and higher volume usage. Pusher, on the other hand, follows a subscription-based pricing model, where users pay for specific tiers based on features and usage. The choice of pricing model can affect the cost-effectiveness for different use cases and budgets.

6. Integration capabilities: OneSignal provides extensive integration capabilities, offering SDKs and plugins for various platforms and frameworks such as iOS, Android, Unity, React Native, and more. It also offers integrations with popular customer relationship management (CRM) and marketing automation tools. Pusher also provides integration options but may have a more focused set of supported platforms and fewer CRM integrations available.

In Summary, OneSignal offers highly scalable delivery capabilities, advanced targeting options, rich media support, in-app messaging capabilities, flexible pricing models, and extensive integration capabilities. On the other hand, Pusher focuses more on real-time communication, may have limitations in delivery capabilities, offers fewer targeting options, lacks native rich media support, lacks in-app messaging capabilities, follows a subscription-based pricing model, and has a more limited range of integrations.