Used to be if you put a google map link on a mobile site, iPhones and iPads would return an error.

I never experienced this on my iDevices. A Google map link would always open in Google, no error.

Apple is still using its own Map app for non-Google links and any other addresses that show up, as far as my experiences have shown.

I clicked on the Map app on my iPad and Google Maps came up...

When I click on the Maps icon on either my iPhone or iPad running iOS 8.4 beta or my wife's devices running iOS 8.3, Apple Maps comes up. What happens when you touch the Google Maps icon?

Admittedly the Apple Maps UI looks somewhat like that of Google Maps but there are distinct differences. For one thing in Google Maps the word "Google" appears in gray in the search bar near the top of the screen. If Google Maps is actually opening when you touch the Maps icon then try holding down the Home button (the round one at the bottom of the screen) and the Hold or Off button the bar at the top left of the iPad when it is held in the portrait position) until your iOS device reboots. That should restore normal operation.

I don't understand it but I know I prefer Google. When I touch the map icon on this here iPad, there is a grey bar at the top that says Google. Not earth shattering, just surprised me.

Maybe the map icon you are touching is not the MAP icon, by Apple?

Yes, it is. The only Apps I ever installed were Netflix, the printer app, ad some silly games.

What may have happened is the Maps and Google Maps icons may have gotten stacked on top of one another. I saw that happen once in an earlier iOS releases. Since Maps is a built in iOS app it cannot be deleted so it has to be there — somewhere.

1. 
   Try this,
   1. Open App Store on your iPad and search for Google Maps.
   2. If you have Google Maps installed instead of offering to Download or Buy it will say Open. If it does then you do have Google Maps installed on your iPad.
   3. In that case I can offer no explanation of how Google Maps got installed but it did and unlike Maps it can be deleted.
2. Alternatively assuming you have Siri turned on and you have a WiFi internet connection or a telco data connection,
   1. press and hold the Pause button (the round button at the bottom of the screen in portrait mode) until a line with a microphone appears
   2. then speak the following, "open google maps",
   3. repeat except this time say. "open maps".
   4. At that point there may be two different apps open.
   5. Double tap the pause button and you will see all the open apps and you should be able to see the difference between the two map applications.
3. Assuming both apps are installed and the icons are stacked as I surmised then a full reboot as I suggested previously should unstack them.
4. Otherwise you may have to go to Settings > General > Reset (at the very bottom of the list) > Reset All Settings. Yes you will have to manually reset everything after that but hopefully that will clear the issue.

I went to the Apps store and Google Maps had a cloud symbol next to it. When I clicked the cloud symbol it started to install. I stopped it. I have never received an update alert from it either.

I like Google Maps. I read the string about GPS and Google and Apple Maps the other day, but I still like Google Maps because I don't go to any remote places, so the issues discussed there are not relevant to me.

I like Google Maps because they are 3-D and I feel like Superman flying around Gotham City. I like Google Earth (which I have not installed on the iPad yet) because I can see Earth from space. Bonus!

If there was a cloud with a down arrow that means Google Maps has been installed from your account on some iOS device at some time, but it is not currently installed on the device you are using. I strongly urge you to reset your iPad as something is definitely amiss.

I never had any other iOS devices. Weird. And it doesn't show up as an app on my iPad. I will reset it because you said to, joemike. My instinct is to let minor things like this go, but I trust your instinct here.

I would be very interested to know if resetting changes anything. As I said there is definitely something amiss here. For one thing several Apple apps on you iOS device are linked to Maps and will not link to Google Maps, plus as a builtin app, Maps cannot be deleted. All of this is independent of whether your personal preference is for Google Maps, Google Earth, or Maps.