I have a Surface RT and had an Acer W700. The Atom on the Acer is 32 bits only and supports 2Gb of RAM. While it's possible to install VS2k12+WP7 dev tools, developing on that setup is practically impossible. Outlook is borderline viable if you disable a bunch of addons.
Battery life is definitely *not* the same. Maybe with Haswell it will improve, but for now ARM holds that crown easily.
Unless you absolutely need to run some Win32 app that has no Metro equivalent, there's no contest on the overall usefulness of a ARM/RT tablet vs a Win8/Atom one.
That said, Surface RT + Type cover >> Surface RT + Touch cover