Hi ADA,
There's some great posts and points above all offering various perspectives and views. To me, stuff like that is important as part of 'evaluation processes' to help in making informed decisions i.e independent views from other people etc.
It's nothing new on this forum from me to try and look at things from a financial, high level point of view for the most part and also to know of and understand the 'personal' aspects as well.
From that, you've basically mentioned what I've spoken to lots of people about in real life, both from the USA to the UK people and UK to the USA people. In your case, you have lived here for 3 years and have now mentioned things in your initial post on this thread. To compare, I've spoken to people who've thought and mentioned the same things within 6-8 weeks and then run off back to the US as fast as a plane could take them, and other's who've now been here 20,30, 40+ years. In short, this sort of decision can only come from you and discussion with your better half and/or family etc.
On the higher level, much as I wish for the UK to pull itself out of the economic doldrums as quick as it can, the indicators and general outlook isn't good for at least a couple more years. The US in some aspects is showing the very early signs of recovery and whilst that will 'ripple through' to other countries again, it takes plenty of time. The amount the UK is in the 'mire' and with the unstability of what's going on with the Euro / Euro countries etc, certain in terms the G8, the UK is likely to be the last to pull itself out of the 'mire' and back into good levels of prosperity/growth again. As a result, the basic requirements of life/needs are still and potential always going to be extremely expensive. Housing, even in this worst of recessions remains at unaffordable (and currently unobtainable) levels, fuel & transport costs are right up there as the most expensive in the world, food and utilities also being very expensive as well. Many people's disposable incomes have been severely reduced and in plenty of cases, none left etc. From your post this sounds as though where you are at - much less disposable income left over,even as you bring in good levels of income. I suspect, you are looking at a longer term view and perhaps don't want to be saddled with a life of debt for your remaining working life just to afford a 'nice home' in which to live here in the UK? tied into that, is of course the most important aspect of your life which is your Kids and their futures. When you directly compare these basic elements of life, there is no doubt you'd be better off in the US. Now to counter that, I do know that medical insurances are and can be a very big part of US based expenses, which then goes some way to 'balancing' things out expenses wise between the US and UK, however on the whole, the balance is still firmly tipped in the US' favour.
Going back to the points earlier, I've seen people via work coming here, via businesses and also via personal routes - family and marriages etc, and quite a few have gone back once the 'honeymoon' period is over and longer term wants in terms of family etc and many have indeed stayed. It's the same the other way around, I've seen, met and know many who've left the UK, gone to the US and either scarpered back here in next to no time and many who've stayed.
I'll be a bit grey and boring here, but like it or not, try to deny it or wash over it, there's no denying that in life everything will revolve around money. That money is what will help you do things, from basics and everyday life and bills to holidays and visiting europe as its so close to the UK (as often mentioned!) when there's a lack of disposable income for those nice 'personal' aspects, there's a reduction in being able to achieve those aspects which invariably leads to thoughts of envy as to wanting them as well for you and your family/kids. No point in living close to Europe for instance if you can't actually access going there !
I think by keeping a dual citizenship in the long run, that's probably going to allow greater flexibility for you and it's something I've seen done very often indeed. You can then move between the two when you see fit, I'm not saying it's easy, but certainly easier to do practically. Perhaps head back to the US whilst the UK tries and does pull itself outof the 'mire' and potentially return later?
I know it's tough to decide, but I always say to have as much information and viewpoints as you can get to help, just thought I'd add mine in there too!
Cheers, DtM! West London & Slough UK!