RT is a restricted OS and I don't know anyone buying them. For the very reason you stated. Microsoft controls what you can install and this means it is not yet a Personal Computer but something of a throwback to the bad old days.
I just purchased a Surface RT for use at college. It is frustrating that Internet Explorer is the only web browser available for the device. I am certain that the device has the capability to run alternate browsers, but will there be a time when other browsers are available? Or is there a way to install other browsers that I am not aware of?