Well, of course I'm biased on the answer :). But to give a not-so-biased answer, I would first try to understand what the project is about and whether RAG is a priority in it.
If the project is leveraging agents and LLMs without worrying too much on context/up-to-date data then Haystack could be a good option.
If the focus is to eventually use RAG then our framework could help.
Additionally, there might be a potential route where both are used, depending on the use case.
Feel free to dm if you want to chat further on this!