We booked and selected the hostels through hostelworld.com and I would use them again. It was super easy to see what the hostels offered, where they were and the reviews were very helpful. It was straight forward to book and they even sent us a PDF with helpful information for the countries we were booking the hostels for. Every hostel we stayed in was fab! We had Wifi in our room and the hostel (which is handy when you are checking train times/looking up how to get to places), some provided a breakfast for low money, they were clean and tidy and all the staff were helpful and friendly.
In Berlin we stayed at East Seven Hostel, this was a little out of the main part of the city but was right near a metro line (again pretty cheap) and the area itself had shops and restaurants. This hostel was particularly good because it gave information daily about the different activities that were on that day - markets, walking tours, swimming, bar crawls and a lot of things started at the hostel/had pick ups from there which was super handy. Our double room was large and airy, there was a wardrobe and shelves to store bits. This was the only place where we had a shared bathroom. This was constantly clean and there were around 2 bathrooms on each floor so you could move around if the one on yours was busy. The shower was large and worked well and there was a hairdryer (quite a decent one) in the bathroom. The hostel sold drinks and had a large kitchen if you fancied cooking. Breakfast was around 4.00 euros and consisted of cereals and toast with a range of spreads. It was a brilliant place with 24 hour access and we met and spoke to a range of people there.
In Prague we stayed in Hostel Mango, another fantastic hostel that reminded us more of a hotel. We didn't have as much information here but it was on the castle side and around a 30 second walk from the Charles Bridge. The staff were helpful and had great wifi connection again. Our double ensuite room was at the top of the hostel with cute décor and a sloping ceiling. Again it had a wardrobe, bedside cabinets and the ensuite was equipped with a hairdryer (although this one was a little weak). They had an out door area which was a little noisy at night however it is expected with hostels and a basement lounge with kitchen, however we didn't really spend a lot of time here. The staff were helpful and there was leaflets at the front desk which was manned 24/7. I would definitely stay here again.
Finally in Budapest we stayed in Bazar Hostel. This hostel seemed more lively in the fact that there were always people around, cooking, chatting etc. Although it did get a little loud at night and our room was right near the lounge area so we heard a lot of the noise late at night. Again the location and size of the room and ensuite were perfect and the staff were super helpful. They gave us lots of information, had a range of leaflets and maps and were always ready to answer questions.
We didn't spend a lot of time in the hostels really but they helped to make the trip great and were a clean and comfortable base after a jam packed day.