Also the previous generation RX 580 cards were very stable.
And "more" hear really should mean significantly more to have some buffer for peak power draw (which often is more than the rated power) because you are likely not forgetting some components (mainboard, connected USB devices, ...).
My most stable card was my Radeon 5870, I bought it on launch day and installed every single WHQL release on it that they ever produced. One game had an issue, but it also had the same issue on NV. I think I used that card daily for nearly 8 years.
I wouldn't worry about stability or crashing on a new Radeon card, but rather if the details about it meet what you need. How are you using it- CUDA, VR, 4K, etc. I still lean Nvidia but I wouldn't hesitate to purchase a 6800XT after looking into my particular needs.
Same thing applies to CPUs. You can't really go off benchmarks, you really would need to benchmark what you're doing with it to matter at all. If you can't afford to buy them all and test, then your use-case probably doesn't matter enough to even investigate, buy whatever suits you. For me, the 16GB included on these cards is very attractive but I'd need to do in-depth research on these new Radeons and their VR performance (which has tended to lean NV, but can improve over time) to make a final decision.
I run Windows 10 and had my system on a Nvidia Geforce GTX 780 for roughly a year before buying an AMD Radeon RX 5600 XT this spring. During that time running the Geforce, I had no issues in or out of gaming.
Running the 5600 XT with the latest WHQL drivers, I have had one very recent game crash (StarCraft 2) but otherwise, just some issues with booting - instead of the Windows loading icon, I'd just get a white cursor in the corner of the screen indefinitely. I would have to hard reboot using the power button. Once it kept doing it and I caved and did a reset of Windows, having to reinstall programs. I've had the boot problem once since then, and the above game crash. I think it's very reasonable to believe these are driver issues.
If you're wondering, I didn't do a clean install, but used Guru3D drive cleaner between the Geforce and Radeon. And then I did do a Windows reset, and have had problems since, so I don't think it's reasonable to blame the driver issues on the switch.