[hevi_jos]

French is an extremely easy language to pick for someone who already speaks English.

In fact, English took from French over 30% of its vocabulary. French was the official language in England of the highly educated until mere centuries ago.

Most researchers in France already speak English.

The huge advantage of the US/UK is one: money, you could become rich and apply your ideas to real products(in a bigger market) much much more easily than in France.

The huge advantage of France: quality of life.

[jacquesm]

And much less pressure to commercialize, there is a lot of fundamental and other research that is not immediately aimed at generating a cash-cow somewhere.