Thanks @audiomuze for your kind words.
You may have interested in this post @brian made. It directly answers the question about Meridian Sooloos collections, but it also talks a lot about our new metadata handling, which is well beyond what anything on the market provides.
In your list of key strengths, we nail all of them, except for the API. We love extensibility, and once we are launched, we will look into determining how people want to extend our system.
I hope you do try out our software when we are released, and if for some reason it fails to meet your needs, I want to hear what we can do to fix it! In the What a Journey post, @enno alludes to the music lover we always wanted to build a system for… I can tell that you are indeed that person. 