I find toe-side harder because I don't have help from the bindings to get the board up on edge -- I have to work it with my ankles. On the other hand, leaning toeside is easier.
What I've found while working on my carving, is that you're never as far up on your edges as you think. It may feel like you've got the board up on a 45 degree angle, but if you have a camera on a pole you'll see your edge barely an inch above the snow.
I also found that when I'm really agressively carving, being even just a little bit back-seat reduces my edge hold dramatically.