Just remember that your xbox isn't as secure as a desktop because not as many security software makers can create software for sale on the xbox. Not only that but gamers tend to click on things more quickly if they look cool, because they tend to be younger, and so the xbox should always be considered insecure.
IE is IE and always will be. But, obviously, Microsoft will never offer a third-party browser on there system. You can hope, but it's obvious that it won't happen. Apps on the Xbox 360 do a better job.
Ive tested out the beta and it seems to work just fine, but i think they still have some further releasing to do to get out of the bugs and such. Will test it once they come up with a new update and post back
Are you finding it easy to visit different sites? Is it stacked with links to microsoft sites? I own a game site and I'm not seeing any traffic from consoles just yet so it must not be widely used, hopefully it will be a hit though.