This is a real must go. I was on holiday with my father, we went to The Halal Guys under recommendation of a friend.
Our hotel was right across the street so we could see that every night the place was really, really crowded so we decided to go.
The portions are gigantic and the price is really low ($6 a huge dish of rice + lettuce + gyro+ chicken). I wanted to try their falafel so they gave us two pieces, no charge. You can put as much tzatziki (yogurt and cucumber sauce) as you want, the same with the spicy sauce. A few metters away you can find another cart that sells beverages (they don't sell alcohol).
Before heading back to the hotel we saw another halal guys on the opposite corner, we asked a man if it was the same team, he told us that indeed they were. The man ended up being the owner of the place and he explained that he was working there since the '90s and in this 20-year period many halal food carts settled on the same corner. The original Halal Guys wear yellow polo shirts, work from 7 pm to 5 am and carry a HUGE line of people.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.