Поскольку я - первый иностранный гость у Инны и Юсифа, здесь напишу на английском, еще и потому, что вполне присоединяюсь к самым положительным мнениям нижеуказанных русских пользователей :-)
Inna and Iosif are simply wonderful hosts, warm and welcoming without ever being overbearing or intrusive. I stayed for 8 nights in their home, which is comfortable, impeccably clean and very well equipped with modern appliances. The room is indeed cosy and bright, with natural light and lots of floor and storage space. The Wifi connection is very strong, the building is secure and the immediate area is very tranquil, especially at night. To prospective tourists from abroad, I would really recommend this place if you're looking for somewhere in the centre that is a bit removed from the hustle and bustle of Nevskii and the canals. The flat is very close to Smolnyi cathedral and park, and is a stone's throw from the leafy Tavricheskii gardens, a green space of the size and kind not found in many districts of the city.
Beyond all these details, what really made my stay was the way that Inna and Iosif welcomed me into their home. They are a lovely couple: friendly, accommodating, cultured and very happy to help with both recommendations on the city and practical matters. Plenty of space was made for me to prepare food and coffee, I was able to wash and dry my clothes in a different room from the bedroom and could come and go as I pleased, without any issues. We spoke in Russian, and I know that Iosif has a little German, but from what they told me, I don't think that either he or Inna have much English. That being said, there are very strong English speakers in their family, as the tone of the listing here suggests.
The best thing about the time that I spent in the flat during my stay was the very relaxed vibe that Inna and Iosif created and encouraged from the moment of my arrival. Everything was incredibly easygoing. Sometimes I drank tea and ate cake with Inna and Iosif as we chatted in the kitchen, sometimes I would be invited to help myself to fruit, porridge or sweets for my breakfast when they were not around. I was also given plenty of space to myself and never felt like I was expected to shuffle around the place anonymously. Essentially, I felt like an adult guest, warmly welcomed into their home and 'free as a bird' (in the words of Iosif when he handed me a key to the place).
I would wholeheartedly recommend staying with this friendly, considerate and respectful couple. If you have even a smidgen of Russian and can navigate the parts of the city centre that are away from the immediate vicinity of the busiest tourist spots, then it really is hard for me to think of a better appointed and better value way to stay somewhere as homely and quiet as this.