My KS-3000 S has been around. I use it on stage to carry a heavy Yamaha CS-15 analogue synthesizer on top of a slight (7,5 kg) Hammond Sk-1 organ/performance keyboard. This top-heavy configuration is no problem for it; if the stand doesn't feel stable, it's because the stage boards aren't.
The stand weighs a hefty 10 kg in itself, adding to the stability.
It comes with a carrying handle, but it is rather too flimsy for the weight, and tends to slide off unless perfectly balanced. I hurt myself on mine (the spring lodaded metal wire snapped out and tore a gash into the palm of my hand) so I have detached it and now carry the stand under one arm instead, and try not to park too far from the venue.