The older version of Olympus Micro, before they've made it Kontakt Player compatible, was the first 3rd party choir library for Kontakt I've purchased. It's content and functionality are definitely limited but sound-wise it can to some degree compete with much more expensive products and you can actually get quite creative with it due to its limitations. For instance, you can control the starting point of prerecorded phrases in order to "create" new ones. From the "Contents" section on the Soundiron website it seems they've added some other new things in this latest version, but I could be wrong as I've not used my version of the library for quite some time.
In my personal opinion, the new price of Olympus Micro is a bit steep for what you get inside, especially if you have a full version of Kontakt which features quite nice sounding choir patches, although it doesn't have legato, even simulated one. But Micro is definitely an attractive proposition for Kontakt Player users who are looking for affordable choir library with great sound.
Personally, I've purchased Olympus Elements on one of the numerous Soundiron 40% off sales and I'm more than happy. I seldom use choir and vocal libraries in my work for now, so Elements, Micro plus free Clara's Vocal library which I've downloaded when it was still available, cover my needs.