Having been here for 25 years and seeing how things change (exchange rates, various government rules affecting pensions/cola, etc), my advice would be:
If you come here at 60, be prepared to go without your pension. If you can't live without the pension, then you're probably better off where you are. If you end up receiving a pension at the expected age, then that'll be gravy.
I came here at 46. The doom and gloomers in the US have long predicted the demise of the social security program in the US. When I turned 62, I started receiving social security. That was, and continues to be, gravy. But there's no telling what will happen in the next few years/decades.
At the very least, have a plan B (escape plan).