Good hotel - among the very cheapest in Sofia. While the facilities are fairly basic, they are as stated and fine for the great value.
Friendly staff, room cleaned daily.
Location is great - attractions are within 10 minutes walk (20 in the snow). Metro 5-10 minutes away. A well stocked, 24-hr small supermarket around the corner, restaurants of various kinds within 10 minutes walk, a bar within 5 minutes.
The hotel is quiet - not problems with noise either outside or in, and comfortable, ensuring a good night's sleep.
TV has three channels in English.
The only grumbles is that the room was a little cold (it was -15 outside, to be fair, but a another, cheaper hotel I stayed in that week was warmer!) but there was ample bedding for this to not be a problem when sleeping.
I would not that the drapes/curtains were not blackout ones, as stated, but this was not a problem.