We were booked into the Jey Negin by a helpful hotel clerk in Tehran. However, if we had known how far from the centre of Esfahan and Imam Square it was, we probably would not have chosen it. It is 1 hour 20 minute walk - and ten or so minutes in a taxi (about 10-15,000 rials if your driver isn't a crook).
That said, the room we stayed in (we booked a double - but got a triple and paid $44.50 per night) was excellent. The beds were very, very comfortable, the room and bathroom was spotless and had a western toilet and great shower.
One strange (but good) aspect of the hotel is that there is no restaurant for breakfast - which is brought to your room when you phone down. You leave the tray outside the door when you are finished. Is a lovely luxury to have breakfast in bed however the room wasn't made up during our three night stay so they didn't replace the cutlery, tea-cups or tea pot and it was an ordeal trying to get more.
The hotel is popular with locals for weddings - sometimes two a night - but we found the celebrations finished very early and so weren't a problem.
The best aspect of the hotel are the staff - one girl in particular was fantastic and spoke very good english. She got us bus tickets, sorted out laundry and taxis. But most of all, when I returned to the hotel with an injured knee (watch out for those open drains in Imam Square!) she was extremely kind - fetching me an ice pack and then getting me some tea and dates. An angel!
Overall I would recommend this hotel, despite the distance. It is a real haven away from the hustle and bustle and so far one of the best low-cost hotels we have stayed in in Iran.