Housing is always smaller than you'd get in (at least the western) US for the same price, and I'd bet that's true pretty much everywhere in Europe. Speaking the same language is useful, but Covid has made it hard to make friends or do much.
Despite its reputation, I find that Europe is far more provincial than the US when it comes to food - a lot of stuff you think of as ubiquitous in the West will be "foreign" food and harder 48 to find. (And if you like tacos, stay on that side of the pond.)
Benefits: it's a lot quieter and generally less dangerous than the US. The NHS is absolutely amazing and you'll never want to deal with the American system ever again. People tend to be less aggressive.
From an entrepreneurial standpoint I'm sure it's much harder to get up and running, but I'm old enough to not care anymore. If I could work legally for a UK startup or tech firm doing basic dev I'd be happy enough and well-paid enough to never feel the urge to start my own ragged little thing again.
It is colder in most of Europe than the US, in my experience (not just living here but traveling extensively in my life). If you're a Cali kid, you will miss the sunlight, especially in the winter. It's like a fucking Joy Division video here from October through April. :-D
I think if my wife and I could afford to split our time between here and Vegas, we would. But that's just not in the cards right now.
But hey, at least they're not on the brink of civil war here and the curry is good.