The best part being if you don't allow it to get online during the initial setup you can go change all the personalization settings. It will only lock you out once you get online and it verifies its not activated. I can deal with just having that watermark when I only boot into win10 for a few specific programs.
It's also pretty straightforward to emulate a KMS server and activate Windows that way. Technically against the EULA, I'm sure, but Microsoft doesn't seem very motivated to do anything about it (certainly not for individual users).