The demo is running WM 6.1, but the great thing is that Samsung has added applications that make WM 6.1 very finger friendly. From what I'm seeing in this demo you almost never need to see any WM 6.1 menus, etc. When you click on the start menu it actually opens up a Samsung menu that is finger scrollable. So that fact that the Omnia 2 isn't coming with WM 6.5 isn't a huge concern to me. I'll still anxiously await some custom 6.5 ROMs though
EDIT: Samsung has updated the site and the phone now has WM 6.5