I work with a few people who live at Dynasty Court and they seem to like it. Another couple I work with recently moved to Parkview from Dynasty Court when their baby got a little bigger because they said the facilities for children were better. At either property you should be able to get about 3000sf for your budget.
The High Cliff and the Summit both have large and beautiful apartments, but the only people I know who live there don't have kids, so am not sure about facilities for children. The properties themselves are somewhat more isolated by Hong Kong standards than a place in the mid-levels. Commute time to Central will be about 20-30 minutes door to door in the mornings - traffic from Stubbs Road to Queens Road can get pretty bad.