The frontend upload is quick and easy to use. Staff have been uploading content on a regular basis without any real problems. JDownloads also has many plug-ins as well, and the ones I've used work flawlessly.
Current version (build 931) seems to have fixed my only gripes (had build 925 previously) which was issues with Google Chrome. It use to be that I could not delete files from the frontend, and also could not Cancel out of a file in the backend. These problems are fixed now! All is good!
Many thanks for your positive review.
Your quoted problems with some buttons in the jDownloads backend, has exists only for some users and has to do with the activated editors and special template settings.