I don't know anyone personally with .io mainly due to the price and obscurity.

I do know people that have moved from privately-run TLDs like .info and .space to the Big Three or .uk after huge price increases. That was messy.

For all the failings of UK law it does still require a court order to seize a .uk domain. Back that primary domain with a less-catchy .com or .net for infrastructure and you have a stable, price-reslient arrangement.