I am sure either one would serve you well. Some may prefer one over the other but it really is a matter of personal preference.

The saber grind is typically stronger because there is more full thickness steel on the saber. The flat generally is a tad lighter and bites a little deeper because the thickness profile is more gradual. I generally like the sabers because they leave more meat in the middle of the blade when I turn them into full convex.

From a wood splitting perspective....the saber grind is probably a tad better because it transitions from thin to thick faster. Same concept as a splitting maul.