Everyone's different
TJ,
I still use Outlook for email and I still use the Outlook calendar.  But on my desk sits my trusty iPad with Omnifocus at my fingertips.  So if I need to refer to my task lists, I just swivel my chair and look at the iPad.  If you're someone that is constantly turning an email into a task, you may not love OF on the iPad so much. But you might just do a 30-day free trial, play with it, and see what all the fuss is about.
One very cool feature:  If you have a task and you need to print it out or send it to someone else (along with all the notes), you can email it from OF.  For instance, I had a long list of things to buy at a store yesterday and all those things were in the notes field.  I emailed it, printed it from my pc, and off I went.  Sometimes I send my husband a list of stuff to pick up on the way home too (much better, right?) 
 
If I were rich and had a huge amount of space in my office, I'd buy a Mac to go along with my PC just because of OF!  But I'll never switch over to a Mac completely because of the investment I have in PC software and the learning curve to go "all Mac".  If the OF people ever develop a product that works on PC's, LOOK OUT!
P.S. Thanks for the kind words about the podcasts.  It's a great group of people and a lot of fun to participate--I just wish I could be on every call, like the old days.  As for GTD Connect, I can't say enough about it!  I think I've been a member for about 5 years now and I learn something new every week.  Best money I have ever spent (I own my own business too, by the way).
Hope this helps.  I'm happy to answer any other questions you have.  I don't often look at the public forums and could miss something.  Feel free to shoot me an email privately.