The top 5 tlds offer a total of 87,880 possible 3LLL combinations- not alot of domains relative to the big picture. Although difficult to peg .info, .biz (as well as cctld, .us) 3LLL domains at present, I see them as good investments, and based upon that, would valuate OWZ.us at about $20. Z brings it down (although seems like branding is possible here -"owes" "owzy", "something zoo"?).
W/ letter other than Z-$30 +/-. Owl.us= $50, Owe.us= $75 Good abbrev.us= $100+/- end-user$??