I recommend staying at this place! The flat has all you might need for your stay - towels, coffee maker, fridge, some plates and pans, even iron and TV. It's warm and there's enough space. Located in a basement of a lovely house in a peaceful neighbourhood.
The distance from the city center can be walkable (we did walk most of the time), but it takes really long so if you want to sightsee a lot or if you are not used to walk a lot, using public transport should be considered (the place well-connected you can use bus, underground or train) .
We didn't have chance to meet Espen personally (as we weren't sure what time we'd be getting there and agreed to hand over the key in a locker) but I'm satisfied with communication with him, he always responded quickly, was kind and helpful.