As with many things in the DR, there isn't really an easy answer to your question. Is Ensanche Ozama a good, safe, clean neighborhood?
That depends on many things. Obviously you aren't going to find too many rich people in this very traditional working-class neighborhood, the "first" planned neighborhood "del otro lado", yet that doesn't make it necessarily a bad neighborhood. The fact that the average home or apartment there currently sells for 2 to 3 million pesos is a good indicator that it isn't home to an army of unemployed peasants with soon-to-be-delinquent children, either.
You have to spend some time there and get a feel for the neighborhood's "vibe" or energy. There is no other way around it. Ensanche Ozama and Alma Rosa get a bad rap mainly because they are the oldest neighborhoods "on the other side" and therefore are looked down upon by the so called elite who can afford to live in the more affluent National District neighborhoods we all know and love.
However, as we all know too painfully, for every five-star neighborhood in the national district, there is an accompanying trash-filled, delinquent-friendly ghetto right next door. I found this out when I bought my first house in Arroyo Hondo and discovered that I could get home faster by cutting through Cristo Rey or by driving up Republica de Colombia Ave and cutting through another repulsive slum that turned out to be only blocks away from my very expensive home. OH MARGOT!
I do agree with the previous poster, however, if you choose to reside in Eastern Santo Domingo, check out the newer developments in Alma Rosa, basically anything to the east of Venezuela Avenue. There are some really nice neighborhoods in there, if you do your homework.