I guess it all depends on what you understand by the quality of life. If you are talking about a high purchasing power you get in exchange for your work then US is second to none, at least according to my research. I might be wrong, because I've never lived in US myself, but I was based in both Europe and Asia and it seems to me that IT salaries vs taxes and costs in your country can get you much further than in other places.

Nonetheless, there are still some spots with decent wages like London (particularly strong in fintech, but there's also lots of startups), Ireland (if you prefer to work for a branch of an American big-co), Singapore and Hong Kong if you'd like to change your environment entirely or even Australia. It all depends on your experience and selling skills though, as in most these places outside of US the difference between a senior's and junior's salary might determine your ability to rent a 3-room apartment vs a 100 square feet room in a shared-house with 8 flatmates :)

Most importantly, choose a place that you have a genuine interest towards. The rest doesn't really matter that much. If you pick a crowdy place you'd get a lower life quality in terms of purchasing power and living space, but higher from a cultural/social point of view and more job opportunities as well, so yeah, that's your tradeoff.