G-11 is a nice area. Calculate your ROI, factor in all costs and see if it is worth it. Commercial property, especially shops are better as it appreciates more and little upkeep is involved. Try looking at relatively new commercial areas - maybe O9 or PWD. I like Gulberg, buts commercial area is massive - demand/supply dictates the rents will be low for quite some time and its still not populated.
Look for shops - F10, F11, G11, E11