To those people who think that the tax issues are a problem for the mega rich only who can afford accountants, who cares about them, yada yada yada.
I am at the £100k threshold at this point in my career and it's not fun paying tax out of your net income to a country you haven't lived in for 20 years.
I didn't expect to be in this situation, at the start of my career I wouldn't have predicted it.
It's not hard to get here, though, when you live in London and work in a city geared job, and by the way - that exchange rate malarky doesn't help. You can easily be on a salary which looks huge in USD terms with an exchange rate that favours Britain but isn't mega bucks when you're bringing up a family in London. The starting point for the discussion about US expats abroad who resent IRS obligations is that they're mega bucks hedges in Mayfair stashing it all in Swiss accounts. Or worse that you're running like an online gambling site out of Costa Rica into the US. The reality for many people couldn't be further from the truth.
Alternative Minimum Tax hits a lot of people. It means that even if you've paid your tax at the highest tax rate in the jurisdicition where you live they only allow you UP TO a certain percentage of your allowable deductions. It's a high percentage but the amount you can end up paying could - trust me - end up being a month's net wages.
But that's okay, cause I'm 'rich' right? I can get along fine with one month's less pay. It's a good use of my family's resources, for sure, filling the coffers of a country where none of us live instead of for example paying into a retirement fund or saving for my children's education.
The one time I needed something when I was abroad (my passport was stolen) they made the situation more difficult than it needed to be.
So the upshot OP is that I would think very very seriously before going down the route of getting your children US passports. Don't feel bad deciding NOT to do it. I wish we had reconsidered it for our children. I wish I'd at least researched whether they could just wait and do it as adults when it was clearer what they were going to do with their lives.
I hadn't really grasped that if they never live in the US or only live there for a short period of time as adults they won't be able to pass the citizenship on to their children. So, I feel like I've ended up saddling them with obligations for a lifetime which may result in them having to go through a complex renunciation process later but NOT with all of the benefits that would accrue, if you see what I mean.