I have the standalone TomTom app' installed on my iPhone & their maps are just tragic here in Sydney Australia.
Forever telling you to go up one-way streets the wrong way, turn at no right turns, not knowing suburbs or towns or street numbers not to mention giving your seriously dodgey directions such as making multiple turns to go around a block to bring you back onto the same road rather than travelling straight ahead on the same road or taking you off a motorway 10 kilometres before it needs to to take you on a pointless scenic trip through congested suburban streets...
After paying $70 for TomTom 50% of the time I have to revert to the present inbuilt iOS map app' so if Apple are using TomTom's data for their Australian mapping they have just taken a gigantic backwards step...