upgrade from DDJ SB2?

Hello. I have been using SB2 controller for quite some time now and have been using it in gigs in smaller clubs. It works quite good and the sound I can squeeze from it is good enough. I want to buy a better, beefier controller, but sound output is the most important feature for me. Which one has a better sound card that I use to get higher output level without distorting sound? I can switch to DDJs 850 and 2000 that clubs that I play in have- and that is also a solid option. However- which controller can give me sound that parallels it and gives me all the Serato options?

I also have many tracks that are wav- 32bit float. What product can give me sound card that will squeeze the most of it? 

Thank you.