My wife has a win7 phone, very similar with the huge icons (part of the reason she bought it was she could see it without her glasses on). However, I hate using it. My android phone isn't what I'd call intuitive, but I do know exactly how to get where I want to go, ie: push the expanded apps button, scroll around for settings. Took about 4 times to find the right settings button for bluetooth on the win7 phone, I knew pretty much where to go immediately on my phone from the start.
So...I'd say ease of use is high as long as you only want what is on your home icons, but not so much after that.
It is just Settings > Bluetooth on WP7. Pretty easy. I do wish they would allow you to pin settings to the start screen. That would be nice for WI-FI. But, to your point, Android and iPhone seem unintuitive to me because I don't use them on a daily basis.
So...I'd say ease of use is high as long as you only want what is on your home icons, but not so much after that.