I'm pretty impressed with Gateron's switches, at least in the form of the Healios switch that they manufacture. Very smooth. Very quiet. Tighter tolerances than the Kailh switches I've used.
The Ergodox EZ has "hot-swappable" switches; you just pull them out and snap new ones in. So you can get the keyboard now and experiment with switches forever.
Edit to add: I have two EZs. I also ordered my first one with Kailh's copper speed switches and found them TERRIBLE. Speed switches are very hard to type on. (Imagine pressing Enter when you mean Backspace. It's stressful!) The hair-trigger on the switches combined with not knowing where backspace was on that keyboard made learning a very difficult experience. I now run Healios (linear) and Box Navy (clicky) on my Ergodoxen.
I would also recommend getting comfy with QMK before your keyboard arrives. Install the build tools, make a Github fork for your configuration, and make sure you can build images easily. You will want to tweak stuff extensively when you are just getting started, as the default layout is pretty garbage. (So are the online configuration tools.)
From the switches I have used it does appear that Gateron QC is more consistent than Outemu or Kailh - but I have handled 10 different mechs at most so the sample size certainly isn't large enough to draw any meaningful conclusions!
