Neptune and ClearML are platforms offering both open-source and managed cloud services for machine learning experiment tracking, with user-based and usage-based pricing models and 24/7 support. While both platforms support a range of features like user access management, security compliance, and distributed training support, Neptune is noted for its intuitive interface, ease of setup, and robust sharing capabilities, which facilitate collaboration through features like persistent UI links and saving view configurations. ClearML offers more limited capabilities in some areas, such as series aggregates and custom analysis options. Users appreciate Neptune for its clean layout and flexibility, allowing seamless integration with different machine learning frameworks and simplifying the sharing of experiment logs, which is often highlighted as a significant advantage over competitors like Tensorboard.