Absolutely outstanding.
I stumbled into this serials by accident. ZGH started off slowly and soon became irresistible. It is a masterpiece of casting, acting and script.
The supporting characters truly deserve to be called that. They make the main character shine, as they shine themselves. The romance is portrayed with a light touch , as are the many struggles and the final resolutions. It bears watching repeatedly. Sanam Saeed was marvelous as Khashaf. I was even more impressed when I saw some interviews of her as a really bubbly, and cheerful personality which showed me her histrionic skills in portraying Khashaf.
Humsafar is another excellent series: starts with a slow, improbable plot but soon is very gripping. Haunting performance by Mahira Khan.
Fawad Khan is excellent in both and is very versatile.
I think Pakistani serials are so good especially because they do not have money to squander on pointless and gaudy distractions and must instead rely on great writing and acting. I have seen some of these actors in lavish Indian movies where they got swallowed by the Bollywood machine.