I use a splitting axe and it works great for me. I have a few tips...I try to swing it as fast as I can. With my old monster maul, I can almost let it fall on it's own but with the splitting axe works best when you really get it going. I also will sometimes start near one edge and usually knock of a small split first. Then the rest of the log usually splits fairly easily. I also try to stay away from the center of the log and hit between the center and the edge of the wood.
I cut mainly locust, hedge, oak, and ash. I use the axe on rounds 12 in or smaller. Larger than that the maul or wedge comes out.
All in all, I like the axe a lot. It splits most logs on the first swing and is not as hard on me as the maul. I also find that it is easier on the hands when the log does not split.