.COM domains rank easily and quickly. I always pick .COM domains whenever possible. I even prefer a long .COM to a short .NET or .ORG. More examples are given near the end.
Domain was created for US based individuals, companies and websites. You must be a US citizen, a permanent United States resident, or a US entity such as organizations and corporations!
You cannot WHOIS protect a .US domain which makes it a deal breaker for almost everyone.
You would think these strict, exclusive requirements would improve ranking, right?