Got myself the K75 Lux in 2017 and it still looks and works like new, finally convinced my wife that mechanical is the better option even though its expensive. she absolutely loves this keyboard and it satisfies her thwokey crave :)

Overall the board feels good, keypresses are responsive - a light touch will register, the palm rest attaches nicely with magnets and feels comfortable, RGB is highly customisable and the board feels solid. The detachable USB C cable is also a bonus, it makes it easier to replace with a longer/nicer cable.
I don't personally have any use for the "tournament mode" but it does work as advertised.

There are 2 issues I have noticed with the product however.
1. There is a rather annoying "twang" sound when typing (pressing softly or button mashing, doesn’t matter) or even merely tapping the metal top plate. ps. This happens regardless of if it’s on a wooden table or one of soft rubber/cloth those desk mats. I was aware of this beforehand when looking up some reviews on this board.

2. Corsairs iCue is powerful wrt RGB control, but is massive bloatware imo, especially if you plan on just using it for the k70 - I don’t need it to measure cpu/gpu etc temps, usage, fanspeed etc - I cannot seem to find anyway to turn those features off other than disabling them under windows services.