When I saw Natal I was really impressed, though its obvious that it is Microsoft's effort to get into the movement control Wii has already got into. Sony's ball on a stick (lol) is even more noticeable.
It is really hard to compare them, specially with Natal, because we're talking about different things as Natal's controller is, well, no controller. The matters I see in Natal is as simple as having no buttons. The type of games that can be played withouth buttons will be restricted. How do you play a platformer without a controller? Man if you jump and run all the time you'll end in very good shape And a shooter? will it be able to recognize your finger pulling the trigger? very hard. That's why I think getting rid of controllers is not quite a good idea, though I still think it's brilliant cus it will open new game options and looks very fun!
Comparing the Wii remote with ball on a stick, I can see that ball on a stick is way more accurate than the Wii remote, though I think this will be fixed with Wii motion plus, so there's no problem; and, as I said, it is quite noticeable that ball on a stick is based on the Wii controller.
What I like of the Wii remote, as raisinghelen said, is that it's not just motion, it has buttons and an analog stick. I like the Wii remote a lot and I think it might be the best and easier to use controller made up to date. It also can be used in creative ways, and even like a NES controller, so it is not limited to just one thing. So thumbs up for the Wii remote!!