Dome on Rottnest is a bit hit and miss.  The coffee's good, the cold coffee drinks are excellent (try Gold Rush on a hot day!), there are a variety of kids options (eg blended chocolate ice drinks with freddo frogs in them) but the food isn't always the best.  The biggest problem here is storage space and the fact that they only receive deliveries from the mainland once a week so there are often things on the menu that are not available.  Some of the food is excellent, some of it leaves a lot to be desired.  The sandwiches, burgers, chips and poached eggs are all good options but personally I would skip the pasta and scrambled eggs as they both seem to be prepackaged.