Americans are generally well liked, even though American foreign policies are not always popular. Norwegian is probably one of the easiest languages to learn for an English speaker, the grammars are very similar. You can almost get away with just learning a set of new words and use English grammar. But almost everyone speaks English, so my English speaking friends have had a bit of a problem learning Norwegian, because you don't really need it.

Also interested; was on a business trip to Copenhagen and Stockholm and could suddenly see myself living in Scandinavia in the future...

FWIW, I was working with a big bank and all business was conducted in English because they were spread across multiple countries.

In my experience, pretty well modulo a couple of things. First, and we might as well get this out of the way now, it helps if you're light skinned because, frankly, many Norwegians are still pretty xenophobic and racist. It's simple to point at guys like Breivik, but the not so secret secret is that there are others. For example, if you're bored, look up guys like Arne Myrdal who tried to bomb an asylum center back in the late 1980s. Yes, that was 20 years ago, but these things go in cycles and Breivik was in the middle of one of them. It also helps to understand that Norway hasn't had a large amount of immigration until recently, so I feel like they're still trying to figure out things culturally. At this point, there're first and second generation Pakistani immigrants in Oslo, but they've had a relatively rough time of it. I still feel like the Somali immigrants are having a really hard time. Generally, Americans, Canadians, and western Europeans are seen as the "good" immigrants. I'm a light skinned Hispanic from the U.S. and I was, for the most part, well welcomed. But, to be clear, there will be racial and national dynamics that need to be worked through. I feel its doable, but everyone has their own tolerance level.

Second, as far as language, there are great resources locally to learn language, such as from the municipal government or the university. Generally, on a personal level, people are pretty helpful as well. In addition, everyone speaks English, so if you get stuck, you can just ask in English and get unstuck. I found that the first three months everyone was pretty good at switching to English to make me feel welcome in conversation. However, after about three months, there was a not insignificant number of people who stopped and figured that I'd be there long enough to speak Norwegian. Candidly, that's not enough time and it was somewhat jarring. For a native English speaker, figure on about two years. For a native German speaker, figure on about one year, but, certainly, language learning is a personal sort of thing that takes as long as it needs to. Overall, I think Norwegians have a difficult time listening to Norwegian in a foreign accent; it doesn't happen that often, so their ear isn't super tuned to it. That makes some early speaking difficult as people look at you like you're crazy. Over time, that moderates.

Professionally, janteloven is a very real phenomenon that needs to be learned and understood. That's a really, really long conversation, but the short version is that if you come in energetically into your first job with some ideas that you want to share, you're going to be in for a shock and many people will think you're a prick. Note, this far more subtle than "telling other people how to do their job". Now, it's not that people can't share ideas. They do, but in a different way and one that can take a bit more time. Play it cool. Go to lunch everyday with your department and coworkers. Go to afternoon coffee with everyone and bullshit. After about a year you'll probably figure it out. I really, really screwed this up at my first job out there. Nowadays, I find it relatively easy to negotiate, but it was a big learning experience for me.

Overall, I do find people there friendly and welcoming, in a very Norwegian way. If you take the time to learn the language, even slowly, and have even a small amount of interest in Norwegian sorts of culture like påskekrim, funny traditional foods, and winter activities, it goes a very, very long way. Norway is not, but any stretch, Shangri-La, but I believe it's very doable as an immigrant. Mostly, it'll come down to whether or not you like living in that culture. Generally, I say it takes two to three years to figure that out.