For solo developers or those working on latency-sensitive applications, Fly.io is the better choice. Its true multi-region deploys ensure low latency, making it ideal for services that require fast responses. Additionally, its scale-to-zero machines help manage costs effectively, although you should be prepared for usage-based billing and a requirement for more operational knowledge compared to fully managed platforms.
On the other hand, if you are part of a product team or a SaaS builder focusing on product analytics, PostHog is your go-to option. Its all-in-one suite offers comprehensive features like analytics, replays, and experiments, and the generous free tier allows for experimentation without a significant initial investment. However, be aware of the learning curve and the potential for costs to rise with high event volumes, which could be an issue if you want basic analytics without the hassle of managing events.