Aight. From what i've heard about that "soldering" issue - it simply makes it harder to remove cooler/waterblock. And "staining" doesn't impact in any way functional/thermal capabilities, only looks. But it might be issue for those that want not just keep using for long time same hardware, but care a lot about selling it later on to others. So at the end it's up to own choice +few degrees better temps or unaffected looks for ease of selling.