I've found them to be pretty worthless against undead. All they do is cause bruising, which doesn't bother the undead very much. I guess after a few dozen bruises in the same location it will get pulped, but one or two axe hits and it's removed. The undead I've been encountering don't have limbs that come back to life on their own. Their necromancer bosses tend to head for the hills as soon as they uncloak and don't stick around to reanimate dismembered limbs. Maybe in an evil biome that has auto-regeneration it would be different. But your run of the mill reanimated corpses I see go down very nicely to an axe in the head, while a mace just fractures the skull (which has no effect on undead if it doesn't also tear the brain).
I can imagine maces would be decent against living foes that feel pain, like goblins and their companions. But hammers seem to do that job even better.
I have always recruited based in initial skill, too, but I'm seriously rethinking that now. Given that almost every melee type that migrates to my forts starts at just 3 in some weapon, and given that sparring works well enough to get skill up from 0 to 3 fairly quickly, I'm thinking of just retraining every migrant macedwarf into whatever other melee weapon I happen to be short of (not a height joke). It looks like level 3 is 1.8k XP, while 14 is 16.1k and level 15 is around 18k. So by the time he's approaching legendary, that extra 1.8k is about 1 level. Would I want a legendary+1 macedwarf when I could have a legendary axedwarf? The macedwarf would be really good at cracking ribs and making bruises, but the axedwarf would be nearly as good at sending heads flying.
My recent fort where my first two migrant soldiers were both macedwarves really made me realize just how poor they are. If I hadn't gotten an axedwarf just before the first undead attack, it would have been ugly. About all the macedwarves did was distract the undead and act as targets so the axedwarf could do the actual damage. Without the axedwarf, those two macedwarves would have just kept bruising the undead until dropping from exhaustion.
Dunno, I may just have a bad perception of them. That's why I asked, to see if others find them more valuable than I do. Maybe I just don't end up with the kind of fights where they shine? Or maybe I'm just noticing their useless hits and not noticing the useful ones because of my expectations? I think I really do need to make a gamelog.txt parser to see if they really are as bad as I perceive. I just need to figure out how to tell "useful" hits from "useless" hits. Sometimes it's not clear until the target gives in to pain or bleeds out. And finally crushing the skull of an unconscious opponent after 30 hits certainly isn't as good as doing it on the first try. But how much worse is it? It's hard to quantify DF combat reports.