The flat is extremely well situated near the BART station for a convenient commute to SF, Berkeley and so on. My family enjoyed the stay and there is plenty of space with a second sleeping room and dedicated living room. The interior and cooking niche is basic, but we'll suited for any dish we prepared. As already mentioned in the comments, it is not super sunny on the ground level, however, our toddler was totally satisfied and with the California weather one is outside anyways.
If we come back to the Bay, we will definitely ask Joe for housing again. He was extremely helpful and gave us a lot of insights what to do in Oakland, so I can highly recommend staying at his place.