I've now done Nine Fine Irishmen. Twice.
We stopped in for lunch during our first afternoon in Vegas. It may not be "authentic" as some have groused about, but it is a fun, cozy atmosphere.
I had the Bangers & Mash. Tasty. The serving was a tad small. (There was only one banger and the "roasted vegetables" the meal was said to have come with were minuscule and hidden between the banger and the mash.)
The husband had a full Irish breakfast, which, to his surprise, came with black and white puddings, which were not listed on the menu. He had no desire to eat either. I had never tasted these, so seized this opportunity. They did not repulse me; they were just kinda blah. So, now I can add these to the things I have done once and don't need to do again.
We stopped in here again on our last day in Vegas for a drink. Sat at the bar. I was drinking wine and my husband was sipping a cider, so we don't have first hand experience, but the bartender looked to mixing up some mighty strong drinks.
I probably won't return only because I don't see myself going back to Vegas any time soon. But, we're glad we stopped in and got to spend some time here.