Swiss passports have been better for longer. Other countries (Germany, Norway, Sweden, United States) are equally as good right now, but that only is because of the current economic and political power they possess, which has mostly been built up through the United States's military and economic might/assistance to build a strong Europe after WWII, a strong manufacturing sector, and timber/agriculture, especially in the Nordic countries. Ask a political scientist and they'll tell you two things: 1. No one country (ehm, United States) can stay at the top forever, and 2. Statistically speaking, manufacturing will not keep a developed country's economy afloat forever. Especially with the current US president, you'll probably see the value of the US passport weaken slightly over the next 3-4 years.
Switzerland's passport is rock solid. The thing is, Switzerland has three things going for it that will keep it afloat for a long long time: 1. They are everybody's friend that's also not afraid to defend themselves if need be (armed neutrality), 2. They serve as an important global economic and political hub because of this neutrality (think Geneva and the WEF in Davos), and 3. They have a very strong service sector, which for developed countries is the singe best future proof sustainment measure for a developed economy. Switzerland's banking industry doesn't hurt in securing its place in the world, either.
Because of all this, Switzerland's passport will be a reliably useable travel document for years to come that will not cause you to be scrutinized while traveling abroad. Remember trying to travel as an American during the Bush years? It wasn't fun. The jeering that came with someone finding out you were an American has never happened with someone finding out I'm Swiss. I've never heard someone go "You're Swiss?! Hey, you know that guy Blocher?! He's a f*ckig racist, you Swiss pig!" (Which he is, btw, and also kind of a cult figure within mainstream Swiss politics.) I have however gotten that with Trump while traveling over the past 12 months. The worst I've gotten about Switzerland is "You must like chocolate and cheese!" Which I do. But then again, who doesn't?
Especially with Trump in office now, I have a feeling we're about to revisit that, so I'm sure the Swiss passport is something dual Swiss-Americans will be increasingly grateful for.