@imrankamal
Asalam Walakum,
I spent a whole year at the Mustafa Towers in F-10, believe me when i tell you this if you are from Karachi and you want someplace decent to live in Islamabad you will find no other place better than Mustafa Towers (may have something to do with the fact that the management team is from Karachi AKD Group)
The place was very clean had water 24/7, security was tight...i was a little concerned about the atmosphere but then its Islamabad and people keep their business to themselves which is great.
Not sure what the rents are right now but back in 06-07 i paid 20k for a two bedroom apartment. Best thing was it was a ground floor and did not have to rely on the elevators.
I have been to the PHA apartments in F-8 and did not like the design or the atmosphere. If you were to rent a portion you will have to rely heavily on your landlord (emphasis on the LORD).
Just my advice. Let me know if you need any contacts for getting a place in Mustafa Towers.