Finished the build on Saturday. It's already pretty dang fast to load software, etc, but you're still not talking about PS5 exclusive load speeds even with a 12900K. I generally target builds at new OSs, so it's great seeing resizable BAR, auto HDR etc. And I'm obviously very ready to take advantage of direct storage too.
I've run multiple raid setups and know the risk. I won't put data on this that isn't getting backed up to the cloud, and you may be surprised to hear this, but installing windows from USB was *pretty fast*. The entire build was done without copying over any data from my old PC. Everything came from the cloud and thanks to Game Pass and Steam that included most of my save games. There's some Epic Games Store games I have that don't use built in cloud saves, but nothing I'm particularly worried about having lost. Starting from an empty hard drive is pretty easy these days if you're invested in Microsoft's eco system.
The main thing would be redownloading whatever games I want to play. Flight Sim took quite a while to download (especially with the free content packs).
Mainly, the appeal of RAID 0 here was as much about giving me a single 4 TB volume to throw games at, vs my old build where my fast storage was circa 800 GB and I regularly had to move and juggle software between that and a large 7200 RPM secondary volume.
One of the most notable improvements with this build so far are load times, but I know we're barely scratching the surface until we get direct storage and games developed for it.
While any game can benefit, something like SF6 isn't the ideal candidate for this, since you're dealing with generally constrained environments, and you aren't bringing nearly as much in and out of memory on the fly. Games with large open worlds like Forspoken are going to most notably benefit from things like this, I'd imagine.