The oxtail soup at the Fremont Hotel Coffee Shop (not the fast food counter) is by far the best in downtown Vegas. The 2's company at the Cal coffee shop or the won ton min comes close, but nothing is more satisfying (and worth my 4 hour drive) than the Fremont's oxtail soup.
The coffee shop in the Fremont is tucked in the back of the casino, where It shares the same location as their buffet.
Our waitress told us that the California hotel and Fremont compete to see who's soup tastes better. Take it from this transplanted Hawaiian, the Fremont wins every time. Your bowl arrives full of meaty oxtail with a broth that is so addictive, it rivals a great bowl of pho.
Take my advice and give this a try. There are few places in Hawaii that serves oxtail soup everyday. Be thankful the Fremont does, but only until 11:00pm. (i know, bummer)
*4 stars is given based on service of staff and oxtail soup. i have never stayed here, so i can't vouch for the rooms.