In terms of build quality, steelseries is pretty good. There is actually a red switch version of 6GV2, and it costs exactly 80€.
From personal experience with a 7G (black switch though), I started to experience duplicate inputs, however considering what I was doing with it, I would say that's not even that bad (it was only "L" and "H", didn't use them anyway).
Strange anomalies appear after several years if you use it a lot anyway (goes for any keyboard). Duplicate inputs appeared about after two years of heavy use for me.
As for the cherry board 3.0, I actually could test it myself. It has slimmer keys than a regular mech keyboard (less travel time yay), however the cable is damn abysmal. The cable is surely the weak point as you can disconnect it manually, so if you move your keyboard a lot, expect your cable to lose contact from time to time, even if it's connected and not moving. It's cheaper though.
Pick your poison.
P.S. if you manage to find a cheap corsair K70, avoid it like the plague. I know several people who are experiencing dropped inputs where keys randomly wouldn't register (myself included). It's kinda late for me to return it though.
/rant off.