Mary,
This strikes me as do you like Lasagna or do you like Steak? I wouldn't want to settle on either as my only food for the rest of my life.
I love OD racing, like my Lightning. I love Manufacturer OD racing like my Hobie 16 and more recently my Mystere 4.3. I love Portsmouth Racing with big starts and lots of traffic playing with all my friends at once. I love Formula Racing because it gives me the freedom to be a "hot rod" as David (davidn) stated. I love PHRF racing. I enjoy my catamarans. I like my lightning. I enjoy sailing my friends keelboats.
With each type of racing, handicap or OD, and with each type of boat, I get to learn. I learned different lessons at different times. I was lucky in that when I started sailing (Portsmouth on a Hobie 16) I had a number of very good sailors who really helped me along. I sailed Portsmouth with my fleet and Manufacturer OD when I traveled. Sailing a Mystere 4.3 and a Nacra 6.0 and a Bimare have made me a better Hobie 16 sailor than if I had only sailed my Hobie 16. Each boat made me work on different skills. Each kind of fleet I raced in taught me different things.
So, why does it have to be OD or handicap? Why are these two options so often considered as competing opposites rather than complementary formats both of which can be embraced by the sailors and regatta organizers at the same time?