This was my first time staying in a hostel so I didn't have very high expectations. I was pleasantly surprised by Pensione Ottaviano. Firstly, the location was perfect....right next door to the Vatican, which means if you are up early, it's a 2 minute walk to the front door of the Vatican Museum, and you miss the queue. It is also a short 5 minute stroll to the metro station, which will take you wherever you need to go. I only used it once, as I found that I could walk from one side of Rome to the other with no problems...everything is very close in Rome, so it's not difficult to walk - and I am not really a fit person either!!
Secondly, the pensione is located on the second floor of a secure building. There is a building caretaker on duty most of the day, and when he is not there, the front doors are closed for added security. All guests recieve a front door key and a key to the pensione front door also.
I booked an 8 person room, but most of my stay there were only 5 people in the room. The room consists of beds which convert to bunk beds, but are not bunk beds all the time, which means it feels much less crowded, and the rooms are also quite big. Linen, pillows and blankets are all provided by the hostel. The beds were comfy...I suffer from back problems, so was a little concerned at first when I saw the beds, as they are metal framed hospital looking beds, but when I layed on mine, there was not a creak or a croak. The mattress did not sag, and I had a peaceful nights sleep.
Free unlimited WiFi available at all times of the day and night was an extra bonus. If you don't have your own computer, they have one there that you can use at no charge.
The staff were very friendly, and knew the city well, with plenty of information for you to take away with you. The hostel was cleaned daily, and although it probably needs a really good spring clean - particularly in the bathroom, it never felt dirty.
Things you should also know....
This is more knit picking stuff that really didn't bother me too much, but just so people know what to expect. At least if you are aware, then you can't complain that you didn't know.
Firstly, the pensione is on a main road, in fact perhaps, 2 main roads, as it sits on the corner of 2 busy streets. There is noise until late at night, and again early in the morning, as delivery trucks arrive, and the tram begins to run again. This did not bother me at all, and I was able to sleep through any noise. In speaking to other guests at the hostel they had the same reaction...there is noise but it is bearable. I brought earplugs, but didn't consider using them at all....and we had the window open every night.
Secondly, the bedroom doors do not lock. To be honest, our door was open most the time anyway, even as we slept. There are lockers in the room so if you bring your own lock, you can put valuable stuff in there.
Thirdly, there are 2 toilets and a bathroom that consists of 3 showers. These 3 rooms all lead onto the main reception/common room/kitchen and because there are grates at the bottom of the doors, any noise made in the toilets or shower, is generally heard by people in the adjoining room...which can be a bit annoying, particularly with number 2's. Also, the shower cubibles are quite small, so in order to have a shower, I found that I had to undress completely in the main bathroom area, and then quickly jump into the shower before anyone walked into the bathroom as there is no lock on the main bathroom area. I only got walked in on once....poor girl. lol.
The last thing I can say is that although I was aware that there was a lock out from 11am - 2.30pm, I didn't think it would effect me, as I had lots to do every day. But when it was really hot, all I wanted to do was go inside and rest. It did become a bit of a pain having to wait until 2.30 every day to go in.
As for anything else, I think that is it....I know it seems I have written a novel, however, I know when I look for reviews, I want as much information as possible. I hope this helps someone in some way.

I´m glad I only had to stay one night at Pensione Ottaviano. There were no airconditioning or even a ceiling fan, so if you plan a trip to Rome in the summertime, I would not recommend you to stay here, unless you prefer sleeping in an oven.
Location wise its ok with the Vatican city close by, but the rest of the area is quite boring at night.
The staff was non-existing and the vibe in the hostel dull.
I´m never going back.

This hostel is close to the Vatican which is good. We had to travel by train to get to other places which wasn't hard. The hostel is clean and convenient. The staff are super friendly and helpful and this is what makes it stand out from the other hostels.

Also very trustworthy and helpful staff. I left my mobile phone and they posted it to me very quickly and effectively. Overall a great experience. I recommend it to everyone = )

Location is great if you are targeting Vatican. If not, go to other hostel. Beds are very shaky and unstable. Furniture in the common room is litteraly falling apart! They really should consider investing in new furniture. They had problems with hot water. Common room serves as a kitchen, as a reception and as a gathering place and it is very small. They give you a personal key (with a deposit). I liked it as it gives you a sence of having your own apartment close to Vatican.
Internet is free only after 7pm. Staff was helpfull though.