NNN.us makes sense, if the NNN is something meaningful, like an area code, perhaps a moniker for some product like "420."
Buy them cheap and hold. It doesn't take a lot of money to hang on to them for a few years to see how it all shakes out. For an alternative gamble to .com, there is truly none better. Yes, I know, a couple of ccTLDs have taken a ride on the inflation train due to hype and mis-characterization of the meaning, such as the ccTLDs for Tuvalu (.tv) and Columbia (.co). Depending on the temporary ignorance of end users for the long-term success of a ccTLD is a larger gamble, IMHO.