we stayed for 5 nights at Kristian's place. It is few minutes walk from sol metro and very centrally located. You can take mtero/bus or even walk to the palace and cathedral towards west. It's about 1-2 kms max. for rest we took metro.
Communication with Kristian was easy and simple. We couldn't meet as he was traveling but that was never a reason of concern. He sent us all the details in advance and was easily available over phone. He also sent tips on place to visit and things to eat.
The apartment is cozy and has more than basic amenities one would need. Everything was clean and in working condition. Couldn't have asked for more. Would highly recommend.