Travelled alone as a young lady and felt safe, and was very pleased with the hostel quality as the single room was large, clean and functional with a sink and mirror, table and chairs, wardrobe and sideboard.
Metro station was only 10mins walk to all the major attractions (Charles Bridge, Old Town) and there were local cafes nearby with mini markets too, where I bought fruit and water.
Did have to share the bathroom and toilets, which I was uneasy about but these were surprisingly clean.
However, bed and pillow were horribly uncomfortable and lumpy, and didn't sleep at all the first night. Luckily, the room had an extra bed so used the duvet as a bed sheet and folded over the 'cushion,' and slept ok. The room was well heated too, so I felt very cosy. The hostel info sheet did say you could ask for extra pillows etc but found this too late!
Also, my room was next to the showers and I was awoken far too early every time they were in use!
There were also communal kitchens, sitting area and reception area with free internet access and 24/7 snacks and drink. Reception staff were very helpful and friendly, and gave me a town map with metro info:)
I felt very safe throughout as a young lady travelling alone, and I didn't bump into any other travellers at all on my floor. I would definitely recommend this place if you just need a clean and cheap place to sleep and stash your stuff.