Here I am sharing my personal experience. I had used ghee of patanjali, dairy best, nova, amul. Among all these brands amul ghee is the best. Other brands ghee are not at all satisfying to eat because after few days their smell vanishes and if used, they can spoil your food item in which you used it. if quality and purity is being watched then also amul ghee is the best and nova is the worst. if I was being asked to rate all the brands on the basis of quality, taste, smell, purity I would rate them in following order:
1 Amul 2 Dairy Best 3 patanjali
And I highly recommend not using Nova ghee in cooking purposes because purity is not guranteed at all.