An annual survey conducted by Mercer Human Resource Consulting shows that Sofia is on 116th place for overall quality of living. In the the sub-ranking for health and sanitation services our capital has reached the 105th place. On EU-scale the positions are respectively 26th and 23th (out of 26, Malta's capital is not included).
According to the survey, there's been some improvement since 2006: from 118th to 116th place for overall quality of living.
According to many Sofians though, there is no improvement at all or if there is, it is only in areas which are not that problematic. My feeling is that the most problematic areas which prevent Sofia from progressing are the poor condition of street covering, homeless dogs, the building boom, etc.