First off I loved the location. Away from the hustle and bustle but still pretty central.
It was good value overall though the bathrooms could have used some looking over. Still pretty reasonable.
I'd say it gives you value for money for a couple of nights in Istanbul though in could surely imrpove in some areas. As far as hostels go, it wasn't too bad.

Very good hostel. Staff were patient, room was clean, location was great - near Taksim Square, tram line, and a small grocery store. Sleep was good. The only minor quibble we had was that there was a mothball odor - a small price to pay for a cheap, clean, private room in a good location. We were out too much to be bugged by it anyway. No bedbugs - my biggest concern when sleeping away from home. Emailed to make the booking and had no problems.

Hostelon was a great choice for several reasons. First, the location is very good. I didn't like the atmosphere in Sultanahmet so it was very nice to stay near Taksim square where it wasn't that touristic and where salesmen behaved politely and did not hassle. Second, the value for money is excellent. It included a small breakfast. The rooms were very clean, everything was new and the place had just been renovated. Third, the staff was very friendly and seemed to enjoy their work thus getting information and tips was very easy. I travelled by myself so it was a good idea to stay at Hostelon because I met other guests who were very friendly. So all in all, the atmosphere was pleasant. A special thanks to the owner who managed to make me feel very welcome.