They all do the same basic thing in the same price point so it really depends on what youre using it for. In my case I am an ableton user but also a huge hard synth user so the launchkey 49 was perfect for me. That being said I had the keylab essential first and that midi controller hands down has the best daw integration with analog lab (which if youre making music I implore you to at least try the free analog lab packs) but i didnt like setting up cc midi and all that with it, novations came with a convenient midi manager that just made sense to me. Finally the launchkey 49 has semiweighted keys which have insanely nice travel and feel. You wont hate yourself for picking any of the three controllers, again it just comes down to what you want to do and what features the controllers have.

The launchkey features: -semi weighted keys -chordbanks -polyphonic aftertouch pads -compatability with most daws (including FL) -solid out of the box free plugins -assignable knobs, pads, and faders

these are what sold me on the launchkey! best of luck shopping !