I lived in Portland for almost 10 years, and loved it there, but you are exaggerating some of these points. Hiking/biking I agree are both awesome there, and the weather in the spring/summer/fall is great usually. The light rail is not that wonderful and isn't nearly as comprehensive as you are making it sound. It is nice if it happens to line up with where you want to go. Downtown Portland is overrun with homeless 16-25 year olds these days, but is still reasonably safe. I don't find it particularly clean, but it isn't dirty either really. Average. I still highly recommend a visit though. If you go make sure you see the Japanese Gardens (if you are at all in to that kind of thing) and Powell's books (the best bookstore I have ever been to, and was at one time the biggest book store in the world I think). Saturday Market downtown is also cool. Damn, now I miss my bookstore.
Well, all places in the United States now have their encampments of homeless and impoverished. 40 million on food stamps...so thats 1 in 6-8 people who need food stamps to live. So there is no way to avoid it and if you are from out of the country then I suggest you watch yourself carefully as crime is on the way up in most every city. Another good place is San Francisco right by the Marina area. It is very touristy and not so relaxed though. I would say its more relaxed then any city on the east coast though. It has bus/light rail system that is also very good. You can take the light rail right from the airport and then use the bus system to get anywhere you need to go. I would say its an all-around cool place to be with lots of culture, nightlife and things to do. If there is only one city I could visit in America and was from out of the country then it would be San Francisco.