I split with an eight pound maul for years. The Fiskars is so much lighter and the handle is relatively short so I was skeptical that it would perform as well. It does a surprisingly good job for how light it is. I do at least as well with the Fiskars as I could do with the big maul but without having to swing the added weight. I suspect most of its benefit comes from the extremely sharp blade but its shape and non-stick surface certainly help.
I wouldn't use it to drive a wedge though and you can't really chase it through a tough piece with a sledge hammer. The non-stick surface works well enough that the head just bounces out of a partial split.
I wouldn't worry too much about breaking the handle. It seems fairly "unbreakable" and, with the lightweight head, an over-strike isn't much of a problem. The handle is integrated into the head so if you were to break it, you'd have to replace the whole axe.
Do raise your work up off the ground. It takes a while to get used to the short handle and you don't want to test its performance on boot leather.