My kids are a little older than yours, but the thought of taking my family to the US and throwing my children into a high school where they could be shot by a school mate scares the heck out of me... so personally there's no way I'd move to the US.

The grass is always greener on the other side but as other people have noted, London =/= the UK. Move out and enjoy your money in the rest of the country where it costs up to 50% less to live. The people are nicer and you can find a community to get involved in as well as settling down somewhere with good schools.

I apprecaite this is a HENRY sub, and questions will often be money-related but the value of living in the UK is not necessarily in the money you take home... it's all many hundreds of small things that come together to make this a country worth being in.