I agree the Android buttons are a bit of a problem. I dislike how every handset maker seems to implement them differently. HTC is a funny example because they use at least 4 different button layouts/orders. More than a dozen if you count clickable buttons versus touch buttons. That's a bit much. I'm not looking forward to upgrading to a device with a different layout in the future. I don't really care which layout is the best I just want some consistency.
The other issue which you eluded to is Back versus Menu -> Quit. I'm always a bit paranoid that Back isn't really closing an application and my battery will be dead so I often re-launch the app and look for a Menu -> Quit option. I have a little mental spreadsheet of which apps I can use Back on and which ones I need to Menu -> Quit on. Android really needs a more sensible way of handling multi-tasking.
The other issue which you eluded to is Back versus Menu -> Quit. I'm always a bit paranoid that Back isn't really closing an application and my battery will be dead so I often re-launch the app and look for a Menu -> Quit option. I have a little mental spreadsheet of which apps I can use Back on and which ones I need to Menu -> Quit on. Android really needs a more sensible way of handling multi-tasking.