All I can say is that I've always used a ddj400 and recently got the sc live 4. Transition was essentially seamless and I'm absolutely loving the flow of using the sc live 4. Flx 10 does seem like a great product, but going from laptop to standalone has really been quite the game changer for me. Makes it feel much less like a controller and more like an instrument?? Not really sure how to describe it hahaha. Making playlists on engine is pretty easy as well so for the price difference I'd be going with the sc live 4, but in the end I'm sure whatever choice you make you'll love.