I paid for it when it was Keyhole, and it was very cheap. So I got grandfathered in when it was sold to Google. I'm not sure what the differences are now. They do send special data sets sometimes (like they sent a Katrina overlay that was good), and that's probably the difference.
I love maps.
No you don't. There are controls at the bottom of the screen for altitute, left right foreward back and turn left turn right. Furthere, your mouse scroll wheel sets altitude (zoom) and left click also works for zoom or tilt, I forget which. There is no difference in the interface based on pay, just content.