I use the regular poleaxe as my main wep, and yes, it is indeed usable in duels. It is abit slow, but makes up for it in reach and pure damage (:hint:stab:hint:). The reach is enough to keep up with the greatswords on the swings, and allows you to outrange the other poleaxes (the Elegant one is pretty common nowadays), and swords without stab (nodachi...). The damage of the weapon is also a very powerful tool for duelling, not just in the sense that you can two-shot almost everything (even tho that is good :wink:), but in the sense that it allows you to strike at odd angles without glancing. If you aim for their feet (less armor, also rarely will you see ppl with loomed boots), you can often hit with sideswings at an angle where you can't even see your opponent (the perfect tool for getting behind him!).
Be aware tho, you will be outranged on by the stab of most twohanders due to animations, and you can be spammed by the faster ones if you don't pay attention. Points put in WM really pays off with the poleaxe, as it helps compensate for ping/lagg when someone tries to spam you. Ath is very important for effective use of the poleaxe also imo, you will never hit any decent player with it unless your footwork is good. (Not so great players can be easily feinted by it tho). A balanced build (21-18, 18-21) is therefore what I would recomend.
Prediction and defence is king when duelling with the poleaxe, once you accept the fact that you have the slower weapon (and when up against the common greatswords, the shorter aswell), and start to play to the strenghts of the weapon, I think you will find it most effective and enjoyable^^
Sorry for the rant, and eventual vagueness, I'm really tired atm x)
It is also a great weapon in the sense that it is extremely versatile, one of the absolute best weapons for battle mode imo. Horsestop stab + shieldbreak + range means that you have he ability to effectively deal with most types of opponents