While reading Shawn's review, this section kinda stuck. Probably because it's completely different from the way I use OmniFocus on the iPhone.
I enter new tasks in the Reminders app (in a specific OmniFocus list), which is automatically added to OmniFocus via the Reminders syncing feature. It's fast, it allows me to forget the idea and focus on what I'm doing right then.
Project, context and dates aren't important at that moment. What's important is writing down what you think about and move on. Later, on on my Mac, I process the entire Inbox and add all the correct metadata to the entries.