LangChain has moved fast and made a decent first pass at a solution to the problem of LLM orchestration. But I'm skeptical that the first solution will be the best solution, and we should keep an open mind to other approaches.
Personally, I like the more declarative approach that Microsoft is taking with guidance [0]. The two projects are not substitutable at the moment, and might even complement each other, but I'm weary of building a new ecosystem on a possibly overly-complicated first pass solution to the orchestration problem.