I'm diving into the exciting world of building AI agent applications and am overwhelmed by the variety of open-source frameworks available. While I've been exploring options like LangChain, AutoGen, Haystack, and MetaGPT, I'd love to hear from the experienced folks here on Hacker News. What are your real-world experiences with these or other open-source AI agent frameworks? Any insights on their strengths, weaknesses, or specific use cases would be incredibly valuable. As a newbie, I'm eager to learn from your expertise and choose the most suitable tool for my project. Thanks in advance for sharing your wisdom!