Plots of Gulberg Islamabad are available in less price then star marketing is offering. Which means there are some issues with this project and at the initial stage its prices are in negative and those who bought now are already in loss. It will be same as Roshan Pakistan scheme who sold thousands of plots on paper but they don't have enough land.
B17 is good project and Multi has good reputation. Phase-e will be handed over in approx. 3 years time. The installment plan is also for 30 months. So it is a long term investment plan but it will give some benefit. The main disadvantage of this sector is dust due to crushing of Margalla side which is very close to b17. Specially phase-a prices r less then other phases because it is very near to crushing site. Also, it is very far from zero point. Though they claim of being close to new air port but in fact they are far away.
I would suggest one option according to your budget. In front of new airport. PECHS has launched its k block. 30x 70 size plots are available on one year installment plan. Development of k block is already in progress and they told to give possession within 4 to 6 months. Total price is 13 lac and down payment is 4 lac. I think you can easily manage it. This location is very good as it is close to new airport and have access through Kashmir Highway also. You can get information about it and plan accordingly.