If you're part of a product team or building a SaaS application, choose PostHog. Its all-in-one analytics suite provides comprehensive tools for tracking user behavior, conducting experiments, and managing events. The generous free tier and open-source nature are great for teams that want flexibility. However, be prepared for the learning curve and potential costs if your event volume increases significantly.
On the other hand, if you're a solo creator or a small business focused on social media marketing, Buffer is the better option. Its user-friendly interface and capabilities for planning and scheduling posts across major social networks make it ideal for managing small-scale social media efforts. Just keep in mind that its analytics are basic and you might face higher costs if you're managing multiple channels.