I very rarely write software reviews, but this developer has earned my loyalty and respect. Developer is extremely responsive. I emailed about a bug and it was fixed in the next release. They requested feedback about desired features. I requested making the collections show/hide via hotkey combo and importing via file extension, and, boom, two updates later I get my wishes. For anyone who has experience with Fences on Windows this is exactly what you are looking for for your Mac desktop. The storage mechanics work a little differently as a consequence of the OS, but the desktop experience is very nearly as polished.