Loved this place. We stayed in a private room with a shared bath. Room was small but had a balcony and didn't spend much time in it anyway since the location is great--right off of Istiklal. The tradeoff is it's loud at night if you're not partying too but we were prepared with earplugs. Beers sold at a reasonable price. Funky atmosphere and cool vibe. Cool common room to hang out in. Friendly staff. Kitchen access but the only place we stayed in Turkey where breakfast wasn't incuded.
BellaMaritimo was just average. We stayed only one night. The location was a bit out of the way but it's a small town so no big deal. Room was a good size and it and the bathroom were clean despite that the place was generally rundown and crumbling. It was hot but the pool was dirty and green which was really disappointing. We were there on a weekend night and it got really loud--music blaring somewhere nearby--around 10 or 11 so bring your earplugs!
Atillas was my favorite place we stayed at on our Turkey trip--clean, comfortable and fun. Out of the way location but path directly from Atillas to Ephesus and regular (free) shuttles to and from downtown Selcuk made it easy. BEST breakfast--so nice to have something other than traditional Turkish breakfast--awesome family dinners for 10 TL, and great vibe. Had a lot of fun playing pool with staff and fellow travellers. Can't recommend it enough.
Yildirim was definitely a great value for the $. The locaation was perfect--only a 5 minute walk or less to all the action but the street is relatively quiet where it is. It was clean, comfortable, and I would have rated it highly anyway but a bonus was having a satellite TV with news in English. The breakfast was buffet-style and above average for Turkish breakfasts since it also included yogurt, fruit, and cheese rolls. Omar was very helpful and we even got us a discount on bus tickets.
Istanbul Hostel was average, which surprised me based on all the great reviews. Stayed in a 4-bed dorm. It was clean and comfortable with a great location for Sultanahmet and nice to have a rooftop bar and restaurant right there. They skimped a little on the breakfast--it was really minimal. It was fine for our first couple of days in Turkey but we chose to stay somewhere else when we returned to Istanbul at the end of the trip.