Regarding Backgrounder, all I can say is that most of us don't really have a use for it.
I've experimented with it on both the iPad and iPhone. I disabled the iOS 4 multi-tasking and put Backgrounder on and found that it did not really enhance the experience over using iOS 4.
I understand the difference. I know that it is possible to configure something to really be "running" with Backgrounder just as if the application were still in the foreground. But I never found that I ever really need that, and it's not like I am a lightweight user.
In other words, I am really looking forward to iOS 4.1 on the iPad. :-)