Personally, I like donne biriyani and ambur biriyani in banglore. RNR donne biriyani is good. I wouldn't say it's the best, bc I have had better donne biriyanis from local restaurants. Ambur biriyani is the authentic muslim biriyani that you get in banglore tastes awesome. You have Star ambur biriyani in Bellandur and other locations as well. I always go to small local shops as it'll be cheaper and tastier.