1. Cost: Mailtrain is an open-source software that is free to use, while Zoho Mail offers various subscription plans based on the number of users and storage requirements.

2. Customization Options: Mailtrain allows for extensive customization of templates, campaigns, and automation rules, whereas Zoho Mail provides a more structured and standardized approach to email management with limited customization options.

3. Delivery Rates: Mailtrain may have reliability issues in terms of email delivery rates due to its self-hosted nature, whereas Zoho Mail boasts high delivery rates with its professional email servers and infrastructure.

4. Integration Capabilities: Mailtrain offers integrations with various third-party applications and services, providing flexibility in connecting different tools, whereas Zoho Mail primarily integrates with other Zoho productivity applications and may have limited integration options with external platforms.

5. Collaboration Features: Zoho Mail emphasizes collaboration features such as shared calendars, document storage, and task management within its ecosystem, while Mailtrain focuses primarily on building and executing email marketing campaigns.

6. Mobile Application: Zoho Mail provides a comprehensive and feature-rich mobile application for both iOS and Android platforms, enabling users to manage their emails on the go with ease, whereas Mailtrain lacks a dedicated mobile application, potentially limiting its accessibility for mobile users.

In Summary, Mailtrain is a free, highly customizable email marketing platform with reliability concerns in delivery rates, while Zoho Mail offers subscription-based plans with robust collaboration features, integrations with Zoho applications, and a user-friendly mobile app.