Portugal is spectacular. COL is very reasonable, and the cities/beaches/lifestyle is wonderful. Like most European countries, they are stagnant and have a population decline issue, but are relatively stable and solid from an energy perspective, as they get ~70% of their electricity from wind. Housing costs are rising, and there is definitely a bit of resentment about expats coming in and pricing people out, but I'd say the feeling isn't too strong.
Officially, the line is that you need to invest 250k in a Portuguese business or investment fund, but according to my buddy that isn't super strict. He was going to buy a bar - alcohol type - to fulfill the initial investment, but found out he didn't have to. Moved to Cascais, a beautiful coastal town right outside Lisbon. I've only been once for a few weeks, but it really is a lovely country and the people are awesome. Best surfing in the world if you are into that.
Your information is outdated. The Golden Visa is now €500k (almost $600k in US dollars due to crappy exchange rate now because of Trump - was 1.08 at the start of the year versus the current 1.19) per person, not €250k , and has become "super strict." The political party Chega, which is fairly strong right-wing, is gaining momentum and power, and is influencing the political climate towards immigrants/expats. They are trying to lengthen the amount of time to become citizens from 5 years to 10, and do away, or tighten even more, the Golden Visa. As to feelings of Americans/tourists/immigrants, in Lisbon and Porto, there are definitely protests and demonstrations due to over-crowding and inflation, especially in housing. It is less seen in most other cities. In the northern town of Braga, where I live, it really hasn`t hit here yet. But the Chegas are definitely here too. But you don't need to buy your way to citizenship/residency, just put in your time by living here. Right now, it takes 5 years of residency to become either one, but that is subject to double soon if Chega gets their way.
Portugal is one of the world´s leaders in renewable energy and has gone nearly two weeks supplying the entire conutry 100% of it's electrical needs without using fossil fuel. But per unit, it has the highest cost in Europe. However, you don't use as much since the weather is so much more temperate than the US.
English is prevalent in the larger cities, but less used in the smaller and rural areas. If you want to fit in, definitely learn the language, otherwise, you will always be an outsider. I have lived here 7.5 years and absolutely love it. Nothing is perfect, but my life is sure pretty close. As to cost of living, this web site is pretty accurate. Here is an example comparison of costs between Greensboro, NC and the town of Braga, Portugal, where I live:
www.numbeo.com
And here is Lisbon versus Greensboro:
www.numbeo.com
My main cost savings is that we don't have a car. We typically use public transportation or just rent a car as needed, otherwise, we walk everywhere, We live downtown and EVERYTHING is within 3/4s of a mile of me, including two hospitals, two large grocery stores, and just about anything else you can think of. I had an appointment Wednesday, in another city about 90 minutes from here, and rented a car from a large company here in Braga for the day. Cost $22US, with full coverage insurance. Gas and tolls cost more than the rental, lol.
I will answer a few basic questions, but the best, most current information can be found online. Facebook is full of great groups for this, including the FB group "Americans in Porto", and our personal group "Braga+ Expat Group." Just about aby question can be answered within those two groups.