I bought Punakea early after it came out of beta and was available for purchase. I'd used Leap and wanted a tool with similar functionality and wanted to support a startup company. Punakea was lightweight and I thought good initially. That said, I found quickly that it can't (for me) handle more then 2 or 3 tags attached to too many files and/or too many files of one tag (I would have it crash when trying to tag 40 or so PDFs or when I was removing tags, it would often crash). I did email the developers who were as helpful as was possible; but my issues continued. I have removed Punakea, all related files and re-installed it, no change. Also, there were numerous times where I would remove a tag, then quit the application and go back a week or two later to find the tag back. This and the fact that for my usage pattern, Punakea isn't want I wanted, has lead me to remove Punakea and continue to search for a potential replacement. Sofar, the best I have found, it the Finder's SmartSearchs; they aren't perfect and not as nuanced, though the Finder doesn't crash on me and I can find files faster then I could with Punakea (also, having to maintain the org structure of the tags was a pain).
It wasn't right for me; but might be for another.