On several occasions I have gone to Muku with friends only to find that they are sold out of an item. Usually rice or the soup, but have also encountered a shortage of beef. I personally find it unacceptable that an establishment could run out of items on such a regular basis. They will also close up to 2 hours early when they run out of something, so make sure you call ahead, or you may end up being incredibly disappointed.
Ramen itself is OK, service can be slow at times. If they were able to remedy their stock issues, it would be a more enjoyable place to eat.