Gosia's place is perfect: clean, functional, with many useful things in the kitchen. The hosts are nice, responsive, and care a lot about how you feel and if you are comfortable at their place. The house is a bit far from the center, around 30 minutes by bus+subway from the University area, and 40-50 min to the center on the southern side of the river. The surroundings are very nice. There is a big supermarket 5 min by foot, and an efficient bike sharing service. I would definitely recommend this place if one does not have a rigorous daily schedule to fulfill and needs to go to the city center for that.