The 3D flyover images are only available for big cities in the US, UK, France and Canada, and they are impressive, but probably not as useful as Google Street View when you are trying to find a location. Note that Apple maps requires a data connection. Maps are not cached and if you are away from any kind of internet connectivity you are plain out of luck. Apple should allow pre-downloading of specific areas, or deal with a lot of user complaints. Google Maps on iOS had the same problem, but several third party navigation apps like Navigon stepped into the breach with onboard maps that work anywhere. Apple isn't going to load the whole country on an iPhone -- users would be up in arms -- but Maps needs a trip-planning mode that will allow you to have the maps you need on board.
Finding a POI
A navigation program is only as good as the database behind it. The Google POI listings are very complete. Of course, it will sometimes steer you to an out-of-business store or restaurant, but Google really does try to keep up. Apple has a good, but not excellent POI roster. In general, here in Arizona, it works quite well, and it seems to be sourced mostly from Yelp. It seems to do better on resturants than other types of businesses. It's generally up to date, but on occasion it misses a location I know is there. I think the Maps app is US centric. Reports from overseas are pretty consistent in identifying omissions, especially in Europe and Asia.
I think the brightest spot with Apple's maps is the way it works without typing. Say, "Take me home," and the app does just that. Say, "Find direction to the nearest pharmacy," and off it goes. Typing and driving just don't go together, and this feature works very well.
You can also navigate to anything in your contacts list by just saying that is where you want to go. The app uses the Siri voice, and the turn-by-turn directions are clear and concise. Google, for whatever reasons, never offered turn-by-turn directions on its iOS app, although it does for Android phones. It's likely Google Maps will be back to the App Store very soon, but whether or not it will have turn-by-turn directions is unknown at this point.
The voice-controlled feature on Apple Maps is superior to anything Google offered on the iPhone. It is a pleasure to use and simply reduces distractions when driving. Note: an increasing number of states won't let you pick up your phone to talk on it, so your options are limited but with Bluetooth speakers there are some safe workarounds.
Maps offers traffic information for the US and several countries. I don't live in a place with lots of traffic issues, but I've seen information appear and Maps warns you when your route may have delays. Alerts are quite clear, with a popup that says something like "Faster Route Available: Due to traffic, rerouting can save 8 minutes." Icons show you accidents, alerts and construction.
There's a big gap here. Apple Maps simply doesn't have them. Apple says it is going to integrate them from 3rd parties, but if you live in a big city and are dependent on public transportation, you are not going to like Maps at all. This may get better, and it will have to if Apple is going to compete with Google.
Apple felt it had to dump Google Maps from iOS. Apple and Google are in serious competition, and Apple didn't want to partner with a company it no longer trusted. It's understandable, but Google Maps had features that simply aren't in Apple Maps yet, and some may never appear. If you are a casual maps user, Apple's app is going to be just fine in most cases. It will get you from here to there with reliable directions and traffic. If you are a Google Maps power user you are going to be unhappy.
The detail, POIs and transportation data are far superior on Google. Street view is more useful than 3D flyovers, as impressive as the technology is. Seeing a 3D rendering of a destination just isn't competition for a street-level view. For now, you can get Google Maps on your iPhone browser, but it is ugly, and awkward to use.
That said, Maps is a terrific and free addition to iOS. When Google Maps returns, you'll have a choice, but will give up Siri integration which is both powerful and helpful. If Google offers turn-by-turn directions, that's going to be terrific for those that want to go that way. Meanwhile, 3rd parties are updating their navigation apps because they will have to compete with the free Maps app from Apple. In the end, their will be a lot of full featured choices. For now, with this first version of Maps from Apple, there are trade-offs and no easy replacements. I find Maps works fine for about 90% of my needs. You may feel differently for your own particular navigation desires, especially if you use public transportation.
Maps features are hardware dependent. Flyover and turn-by-turn navigation are only available on the iPhone 5, 4S, iPad 2 or later, and iPod touch 5th generation. If you have an older phone, you'll get maps, traffic information, and local search with directions.