I am not sure why Milvus is so popular. There are other pretty good options like Weaviate and Vespa - both are open source. One important limitation of Milvus

I am not sure why Milvus is so popular. There are other pretty good options like Weaviate and Vespa - both are open source. One important limitation of Milvus that I cannot ignore is that it does not support pre-filtering like Vespa and a few others do. Pre-filtering is critically important for use cases in e-commerce etc. where filters based on structured metadata are applied e.g. brand, category etc.