I have a few reasons for switching....

I am tired of counting carbs and cannot see that as a lifetime thing for me.
I'm trying to get away from all the saturated fat on Atkins.
I'm tired of the negativity you get from others regarding the diet (Southbeach just seems to get a better reaction from ppl)
I want a way of eating that will help lower my cholestorol and help my heart
so I do not suffer another heart attack.
I dislike being in ketosis.