Features are equal, however iPad is slightly better supported. For iPad there are ways to install the web application on the home screen and open it full-screen. Android will require installing a separate browser, and also the browser controls and status bars will be always visible, taking the screen space.
Also to work comfortably a rather fast Android tablet will be required (such as the recent Samsung Galaxy). It will also work on cheap Chinese tablets, but will not be as responsive.
Thanks,
George.