First, the iOS 5 App wasn't written by Google, it was an Apple-written client for Google's servers. It certainly wasn't google's android Maps app with turn-by-turn disabled. Why Apple couldn't add that, or switch to Google's vector maps, is something that Tim Cook and Eric Schmidt and Tim Cook know and we don't, but its difficult to comprehend why a sackload of money and maybe dropping a few lawsuits couldn't solve the problem.
Second, if you like turn-by-turn so much that you'd sacrifice, accurate, detailed maps, decent satellite imagery, street view, public transport routing, localised road colour-coding, then good for you. Personally, I can't see the use of turn-by-turn if it isn't based on solid mapping data.
I think some of the people who seem to like Apple Maps (i.e. those people who didn't start up Maps, go to their home location and find it underwater or, on satellite view, obscured by clouds) are going to have a nasty shock when they actually go on a trip to somewhere they don't already know.
Open your eyes and look at the examples that are being posted: it's not like AntennaGate or FrayedCableGate where you had to take people's word for it that they didn't live in a cave or abuse their cables: the cloud-shrouded areas, the city blocks with missing detail, the useless recommendations for public transport apps, the absensce of street view... they're all in plain sight.