Well the DDJ SX is untested yet but looks promising. It also resembles CDJs very nicely from what it seems and you will find most features in different places on the CDJ 2ks. Also you may not be a controllerist, but the extra features are something to expand on and also non-controllerists use F/X and samples.
I also never had the XDJ Aero, but the workflow seems very different from CDJs and as a personal factor I am not so fond of rekordbox and also dislike WiFi in clubs. (I tried to use touchOSC a few times and it got me into trouble in one gig…)
I think you have to decide first if you want to go CDJ or controller.
At this time I see nothing the Beatmix cannot do for you as well as any 1k controller.