It depends on the person. Some people will only use Android, some people will only use iOS, and some people will use a mix. All three situations are perfectly fine. What is NOT fine to me are the people who refuse to accept that all three of those choices are acceptable (including all the ignorant people on here who think that just because someone likes the iPad 2 for what it does that the person is a troll or should be hung by a noose and set on fire).
It all comes down to what you would be using the devices for and which one provides you the most value. For me personally, the Xoom is my tablet of choice due to what I use it for. However, I see the great value in the iPad as well. It's just not for me personally.