Are .coms that much more superior than .us domain?

I just finished the book and have to say I'm thinking way differently now. I think I have found a great idea that could fulfill the need of millions. The problem is I'm having a hard time finding a good .com domain. Most the ones I like are already taken or too expensive. The one I really like is for sale at 28k however the .us version is only $3.99. My main question is are .coms really that much more superior and am I making a mistake purchasing a .us domain?

Also I see some other domains...

Are .coms that much more superior than .us domain?

from Are .coms that much more superior than .us domain?