I just searched for this features: TAG/COVERS from discogs, beatport and find only these two:
http://www.tspotter.net/
some great tagging options, and I dont like it directly open collection.nml file from traktor, but again it was made exactly for us

http://getmusicbee.com/
no more info on this except beatport,discogs tag,cover import

I dont like any program messing with my music files, except traktor and tag&rename, but eventually I will have to update all my collection with coverart and some tag fixes.

I found out songbird http://getsongbird.com/ and it has android apk too, and discogs tag/cover import. They are planning some updates so maybe it will include beatport.

there is other programs but you depend a lot from few developers and forum members for making scripst for juno and beatport so you will have to follow them on their forum for any updates(like http://www.mp3tag.de/en/).

please suggest any other programs.