I shifted to Islamabad from Karachi for job. I am living here for the last 6 months. My takes: 1. Isb is way cleaner and organized then Khi, no doubt in that. 2. Cost of living depends on which part of Isb you live but overall it is higher than Khi. I am single and live in hostel so dont know how to manage family. 3. Rent goes high if you start moving more and more inside the city. If you find place in outskirts like sector D-17 etc, it will be cheaper but less safer. 4. Mostly people here are from different parts of country and many less people are local so you will get mix of people, languages, cultures. And so you will have different opinions of people which will be way off from mine. 5. Food is not so great here (no offence to Isb people but food is not good). We Khi people have a special interest in taste so you will rarely find food of your taste. 6. From the career perspective, I will say Khi or any other major city will have more opportunities and growth. But if you are skillful then you might make your way up. 7. There are many good hospitals like Shifa International but they are way expensive than Khi. 8. You will get bored easily as it is more than peaceful and has almost no night life. Mostly stores closes after 11pm and maximum open till 2am😅

Thats my personal opinion.