I've been here a handful of times with friends and definitely recommend it. The food is decent, the portions are huge, and it's never too crowded. One of my biggest fears when eating out is not being full when I leave, and that is especially true at noodle houses; however, Republic Ramen serves their noodles up in gigantic bowls that will challenge you to finish them and slurp up all that you can.
Ramen is what you make of it, and you aren't doing yourself any favors if you don't add some spices. Be adventurous and don't be afraid to try things that you can't pronounce. You'll thank me later.
P.S. the attached boba bar is decent. It may not be the best boba in the world, but the huge variety of flavors that they will let you mix and match can lead to some surprisingly savory drinks!