Some pretty good, keyword .us domains are available / going for very little $$$. I personally think that they are pretty good considering I live in the US. What's so bad about .us domains?
Nothing's bad with them. But, it's the same as owning a .de etc. domain. It's not a .com/.net/.org and as such, not as popular or valuable.
There are many in the domainer community that feel .us is underpriced. I tend not to agree as I believe the American mindset is CNO. However for development potential if you can get a .us at reg fee then it's probably a well valid reason to register some. I do own a few myself.