Works well, no hiccups.
I think a few additions could really make this really worth the $45 price tag (which is awesomely down from the $105 price it was at in 5.6). It could be a little more robust (suggestions in order of importance):
1. a filter by file sets in addition to the keyword search
2. the ability to show all file sets *except* selected file sets so a site admin doesn't need to go in and add a file set to the library every time a new file set is added
3. a way of forcing the user to input a good file title and select at least one set (without requiring this on a free-for-all upload, you end up with a messy file system)
Those 3 items would really, really set this add on apart and make it a go-to for basic file management.