> Apple seems the easiest to work with as long as you maintain an account and a credit card in every country you want to deal with.
Why not deal with one country only? I have been using my German Apple ID quite happily on three continents. I may miss out on some movies, music and especially iBooks, but there are plenty of other sources. The only hard downside is that some local apps are limited to the respective App Store, e.g. the Australian Optus Mobile (carrier) app.
I think Apple's account system is needlessly complicated, but what problems are there if you stick to one account?
Yes, that is what makes Apple's way superior to Google's; your valid account from one country doesn't stop working when you go to another country.
But there are still reasons to use two accounts. In Japan there are apps which are only available in the Japanese app store (although I cannot understand why). For example, I use some navigation apps and my wife uses some cooking apps that are only available in Japan.
Developers can select the country app stores their apps are available in. It wasn't relevant for my app but if an app can't really be used in the other country why risk support requests and bad reviews when you might actually want to launch a functional version there one day.
Why? To use the examples of the grandparent comment: there are always overseas Japanese who want to cook, or tourists who want to use a local navigation app. I can only come up with legal reasons, or bandwidth preservation maybe.
If you meant Google a/c attached to an Android device then I would like to differ. I created an account in Korea and used it extensively in India and it also worked well in USA. And yes, on all the three places more than one device was used with the account, over the time.
There's my friend who bought his iPad in Holland and he is in India now but the language of his iPad app store is still Dutch. He says he can change it but that comes with some trouble he is not willing to go through.
There are country specific apps on almost all the app ecosystems.
Why not deal with one country only? I have been using my German Apple ID quite happily on three continents. I may miss out on some movies, music and especially iBooks, but there are plenty of other sources. The only hard downside is that some local apps are limited to the respective App Store, e.g. the Australian Optus Mobile (carrier) app.
I think Apple's account system is needlessly complicated, but what problems are there if you stick to one account?