Inspired by discussion on this thread, I spoke today with one of my (Polish) colleagues about their experience around Brexit and getting settled status.
He told me he'd applied ages ago, that he found the process quite simple to get through, and that he got a positive result for him and his (also Polish) wife quite quickly. He also said that he hadn't heard of anyone he knew, either through work or elsewhere who had significant difficulties sorting it out.
He also volunteered the info that he and his wife are currently applying for British passports, which they can have without giving up their Polish passports/citizenship. As I understand it, there's nothing more complicated to this than a normal passport application for a UK national.
Another of our colleagues is from Lithuania, which doesn't allow its citizens to have dual passports, so he (again as I understand it, this is secondhand info) has chosen to retain Lithuanian nationality for himself and his family, which is fair enough.
There are a few other colleagues I'm aware of who may be in similar situations (one Italian, one Slovak) so I'll ask them about their experiences if I get a chance.