After my recent Appigo misadventures and Evernote bugs I decided I needed to look around. Again.
I'd been hearing good things about Things.app, but the desktop app is still pre-release. No import/export.
So I took another look at OmniFocus. No real import capabilities, though they'll sync with whatever's in iCal. So if Bento weren't so slow and feeble I'd move my data into iCal and then OmniFocus. If.
I really don't see any great options, so I'm still with Appigo for the moment.