There are few fast food chains with decent food in Sydney, IMO.

Sydney:
If you like Chinese, Super Bowl has numerous shops around chinatown, so it's cheap and cheerful dining that is a step above fast food. There are some great Chinese cake shops too (which might be chains...). Just ask kaukau.

The theme for Sydney is great quality, reasonably-priced local ethnic restaurants, some of which have more than one outlet or restaurant. Some of the best have only one outlet, so I'd never recommend a place purely on being a chain.

Black Stump, for example, must be the worst example of an Aussie chain restaurant - be warned! It's not terrible, but terribly ordinary!
(We have some really ordinary American chain restaurants here and I don't understand why anyone would go there, except as a novelty!)