I went into Holsteins with high expectations, and unfortunately was let down. The service was quite slow for 6 people and the food was underwhelming. We each ordered burgers, but I didn't think anything was special about it. I also had onion rings. I was a bit annoyed when I asked if I could have half onion rings, and half fries. The waiter replied "We won't customize anything here. Even if you wanted your burger cut in half, we would just give you a knife."
That for me makes me give Holsteins 3 stars. I had the grass hopper milk shake as well (with an extra shot). The problem with service being so slow, was that by the time the food came, I had pretty much finished the milk shake and was quite full.
Overall, Holsteins is not very memorable, and I would rather go to BURGR or Burgar Bar. There clearly was a reason why Hosteins had no wait, and the other burger places did.