I am a resident of DHA Phase 2, rather I am among the first 10 residents of DHA phase 2. Dont go near sector B because majority of the portion is filling and you will have to construct a basement. I am near gate 1 and in sector A. What I kept in mind while going for sector A:
1) I wanted to be near to Rawalpindi
2) the plot was table top and south facing
3) Easy to approach from the gate
4) the plot had no transformer, street light, telephone box installed in it so my green belt is also empty
5) It was near to the bank, petrol pump, DHA offices, market, mosque, dry cleaner.
6) There were no 10 marla plots close to my plot, the 10 marla residence started about 30 kanal towards the left to my plot
It entirely depends upon the location of the plot, price and facing, only then u can make a decision. Apart from filling all the sectors are nearly same.