I have two children (4 and 2) and we see Dr. Clifford as well. We have been very pleased with the practice for the most part and for us, their general philosophy (e.g. they don't believe in prescribing antibiotics for every illness) has worked well. The only thing that has been somewhat problematic is occasionally waiting longer than I'd like to to see the doctor, especially during cold/flu season. I have several friends that use Dr. Milici and they speak well of her. I, too, have heard good things about Dr. Spaeth, but my children have not been seen by her. I have not heard one way or the other about Dr. Becker, but I would assume he is good as well.
Definitely interview them as I think they are all well-qualified. Then you can find out which one meshes best with your personality because that is very important.
Good luck!