This is the first restaurant I go to whenever I visit Vegas. No joke. Me and my gf eat here as soon as I get off the plane, it's that good. We first tried Monta before it received all of its well-deserved notoriety, and were able to get seated right away. Not anymore; expect long lines until near closing time. The atmosphere is very authentic, very small and very loud and simultaneously chill. Service is excellent despite there being only two people working the floor at any given moment.
I always order the miso ramen with extra chasu. It used to be my favorite until I noticed that it got a little saltier in the last few months. So I've switched to regular Tonkotsu. What sets Monta apart, in my opinion, is the melt-in-your-mouth goodness of the chashu, and the depth of the broth. I consider Monta to be in the top 3 pantheon of ramen in the Western US, besting Daikokuya in Los Angeles and Hakata in Gardena. You must try this place if you are in Vegas.