KFC, McD and subway all close to me. Have one every month or so. It is cheap and as OP said reliable in terms of delivering to expectation. Burger King (for burgers) has a better range IMO but there's not one near to me. I used to love going to Gregg's at Uni and getting a baguette, but I haven't been to Greggs for years now. I'm not a fan of takeaway pizza though - I would rather have a kebab. I don't like it when people (and the press) constantly slate these places for being "unhealthy". If you don't like the food then fair enough, but if you do, having a meal there occasionally is not unhealthy if you eat proper food for the rest of the time. If you only ate oranges all your life then that would be far more unhealthy.
I've never eaten in Nandos.
On the subject of KFC, I think the original recipe chicken is much better having been sat a while. I had some in Exeter once and it was served to me straight from the fryer - it was very hot but very tough.