I highly recommend DJ studio. I purchased my license from Thomann. they sent me an email with the license number and links to download the software. Set up could not have been easier.
DJ studio is incredible piece of software. I can link to my Traktor collection/library import whatever songs into DJ studio. The software has an automix function, where the software checks the BPM & key and makes the best mix from the chosen tracks.
However, I like to do my own transitions, using the built-in effects, volume controls, base swap, Crossfade and of course stem separation. I think the quality of the stem separation is excellent, My favourite thing to do in DJ studio is to copy the stem vocal to one of the sample lanes, drag it under the beat of a different track and magic happens. if you are into remixes bootlegs or just like playing with music I highly recommend DJ studio. my only drawback of the software is, from the date your license is activated you only have one year to get free updates. However I will say DJ studio are banging out the updates non-stop.