It really depends on what fast food really is. If it's quick service takeaway style, then HK has some excellent fast food in the form of rice and noodles, and of course the usual McDonalds/KFC's. I once had a KFC that consisted of chicken and mushroom rice, coleslaw with ice lemon tea. On the other hand, I'm not a fan of British fast food as it's mainly generic burger and chips and it's not exactly cheap.
That being said..some of the best burgers I've ever had were in Asia in the form of Mos Burger and Triple O burger joint, my friend who was in Singapore mentioned some holy grail of burgers called Ramly burger, is anyone familiar with this?