If you want to know about Hyderabadi delicacies you should rely on a Hyderabadi's recommendation.
Best Place to have Biryani is Shadab.(Near Madina, Charminar).
Second is Bahar cafe, Hyderguda Branch.
Third Shah Ghouse(Ignore any rumors you heard about this place its all crap and fake)
Other places like Dine hill is famous for their Mandi Biryani which is Yemeni Biryani.
The reasons why I haven't added Bawarchi, Paradise and Hyderabad House is they use to be good not anymore. Since their client base increased their quality decreased.
N no way Astoria Biryani is good. They add more than required ghee to biryani.
another place I love to have biryani is Ulvacharu Biryani from Sweet Magic in Vijayawada.
Just off topic.
Sambar rice in Megha city near Basheerbagh commissioner office is awesome too and you should definitely try
Hotel Meridian, Punjagutta [near Hyderabad Central]
Cafe Bahar, near old MLA quarters, Himayatnagar
Grill 9, Kharkhana, Secunderbad
Bawarchi, RTC X road
Hotel Garden, near Clock tower, Secunderabad
Paradise, Secunderabad [They have maximum branches and may be the highest business in twin cities of Hyderabad]. Though they are at bottom for taste; people go to have for good hygiene they maintain. In terms of kitchen hygiene Paradise can be ranked # 1.
The rice quantity of biryani provided in Hyderabad; I do not think is a match in any of the Indian cities.
Hyderabad House also had good market and fan following; post 2009 I saw they declined in business - In early 2000 they had the maximum branches in the city and all were closed except the few.
Following Paradise model closely is Karachi Bakery - they have expanded in Hyderabad and other cities.
Though they have good products; they seem to be too pricey these days.
The novelty has been lost and today carrying Fruit and Nut Biscuit to friends and relatives; we do not feel that to be novel one.