I always preferred a clean install. Also I'm not a fan of working around...OEM licensing rules.
I've seen many techs who did this over the years, way way back in the DOS and Win3x days it worked fine. With Windows 95...it started to get flakey, esp if the motherboard model was different (not to mention the CPU, and other devices like video, sound, various chipset components). You could tell the real amateur tech jobs....the desktop would be half safe mode looking, "standard VGA video adapter"...lol. Some techs would know to install other drivers like video, sound. But if you looked at Device Mangler, you'd see a mess of other unknown devices, and yellow exclamation marks. And some more thorough techs would clean that up more.
As operating systems evolved...Windows got a little more "tolerant" of this. Yeah going from Intel to AMD or visa versa wasn't always a success. And/or the hard drive bus type would be another key.
However, I have noticed...computers that have had this approach done, are more likely to be the ones that have odd quirks....like, power management doesn't work properly, or...for those who are into gaming with intensive graphics, those are the computers that are more prone to "CTD" out of the game (crash to desktop).