To clear up the confusion: A few years ago, Serato Itch was fused with Serato Scratch Live, forming Serato DJ. I used all three of these and am now happy with Serato DJ =)
Serato DJ, and really any professional DJ Software I used is pretty limited in regard to metadata-based automation. And this is where JRiver excels. So what I do is the following: If I get a new song, I tag and archive it with JRiver.
All songs are tagged with a DJ-Rating tag (5-Star), which I automatically transfer to the Grouping tag (Only one which Serato can read, misuse, I know
). Also, all songs get the Release Date, Date Archived (a time stamp I add upon saving the song to my library) and the mentioned Genre/Style combination. Plus some additional less important stuff. Then I use "Rename, Copy, ...." to save them to my music library on my NAS, automatically putting them either into an Artist\Album or Genre\Style Filepath-pattern (depending on whether I bought an album or just the newest pop song). Syncing software keeps that library synced to my DJ Notebook. In JRiver, I have prepared a DJ-View, which only includes songs with a DJ-Rating >= 3. This view is grouped by Genre and then Style, and alternatively by Date Archived.
When preparing for a gig, I open both Serato and JRiver, and just ClickDrag the categories form JRiver into Serato folders that are structured according to JRiver. In the same manner, I export a chronology, so I can see my recently bought tracks. Then I do Serato-specific post processing (Analysis, Cue Points, Loops, etc.). Playback happens exclusively in Serato DJ.
In this regard, JRiver easily saves me around 40 hours each year in comparison to my previous work flows, making the master license an absolute no-brainer. I would go so far as to say that JRiver gives me a competitive edge, because I can organize a far larger collection than many of my colleagues.