I paid $75 for the OmniFocus 4 upgrade from v3. I figure I'd give the old OF another run. It's a very powerful app, but suffers because of it. Still, I love the built-in review feature. Also, I'm trying to move tasks out of Org-mode, so this was incentive. At the rate that OmniGroup updates OmniFocus, that $75 should last me three or four years.