I am a Spaniard who was fortunate to qualify to a US visa, so I was able to come over. I have many friends who went into CS, but didn't have the chances to come over as I did. As far as Spain goes, what I am able to make in the American Midwest pays for an entire team of developers in my hometown, who don't get more vacations than I do, and often work far longer hours.
And it's not just Spain. A local company here has started a Polish development center, because despite the language barriers, and the time difference, it's hard to pass up a total cost per employee of about 1/4th the equivalent developer in Missouri, and those Missouri developers get a month of vacation, and nobody works more than 40 hours a week.
If the concern is just places with bad work/life balance, we can find them on both sides of the Atlantic. My brother in Spain works 60 hour weeks more often than not, just like some people I know at very large online retailers. Those kind of situations can happen anywhere: But in some cases someone gets to choose it because they like the RSUs that come with it, and in others, it's just that the local market really is that bad.
So if I were you, I'd look in detail, as a generalization on work life balance might be very different than you think once you are on the ground. Take a look at "The trimodal nature of the European software market". There really are very few jobs in the top tier, the second tier is quite a bit worse than the US's second tier, for similar work/life balance, and the third tier is so far from the US, you might as well be comparing working conditions of Software developers with Uber drivers.