As part of a celebration event organised by a customer my boss and I stayed in this hotel for 3 nights in September.
I was told that the options in Tehran were limited, and that is why my review is not as bad as it would have been in other cities.
On international business standards, I must admit that the hotel is lacking the right infrastructure and setup: internet in the room is extremely slow and basically not adequate to work on, the breakfast has limited choice, although the quality of the food was not bad, the rooms are not redecorated in probably 20 years and are still in the '80's style.
That being said, we had a general good feeling with the service that was offered to us. People seem to be genuinely helpful and do their best to offer good service. This does not include the bellboys however who make it no secret they are doing everything for a nice tip, preferably in dollars or euros.
In general the hotel was allright, although one should adjust its expectations.