Why would you think it is easier to use a program made for an open source os (the core of android isn't open afaik), instead of a program made for a non open source os?
I have had android, and changed to iPhone 4, and my impression is that the apps for the iPhone is generally higher quality than the ones I tried for my android phone.
By higher quality I mean that they are running more stable, and isn't making the phone noticeably slower while running in the background, where the last was a really big problem for the phone.
But up to you how you look at it, I just don't see why it should be easier to make programs for, just because it is partly open source.