Our stay at Sergio's appartement was perfect.
It is very well located in Milano, it is only a few minutes walk to go to the duomo and there is public transportation right next to the appartement.
The room was quiet, the terrace was really nice and AC was a big plus.
You just have to be aware that there are a few stories (4-5) to climb by the stairs, but it's worth it.
We strongly recommend Sergio's place.