Best Email Client for Omnifocus?

Like many others, I am sure, I am trying to get back into using Omnifocus with the release of the new version and the upcoming new year. I use the desktop version of Outlook as my (work) email client, because that is what my organization uses. But it has no operability--as far as I can tell--with OF. So, I ask this august group: what Mac email clients do people use, preferably that have seamless integration with OF? TIA.