1. Cost: Fluentd is an open-source data collector that is free to use, while Splunk Cloud is a proprietary tool that requires a subscription, making it a more expensive option for companies with tight budgets.
2. Scalability: Fluentd is known for its scalability and can handle large volumes of data efficiently, while Splunk Cloud may require additional configuration and resources to scale effectively, especially for larger data sets.
3. Customization: Fluentd offers extensive customization options, allowing users to tailor the tool to meet their specific needs, whereas Splunk Cloud has limitations in terms of customization, potentially restricting users from achieving their desired configurations.
4. Community Support: Fluentd has a strong and active community that provides support, documentation, and plugins, while Splunk Cloud relies more on its official support channels, which may have limitations in terms of response time and solution availability.
5. Ease of Use: Fluentd is known for its simplicity and ease of use, making it ideal for users who prefer more straightforward setups, while Splunk Cloud, with its advanced features and configurations, may have a steeper learning curve for new users.
6. Vendor Lock-in: Opting for Splunk Cloud may lead to vendor lock-in, as users become dependent on the proprietary technology and ecosystem, while using Fluentd provides more flexibility in terms of transitioning between different tools and services.

In Summary, Fluentd and Splunk Cloud differ in cost, scalability, customization, community support, ease of use, and potential vendor lock-in.