I always feel that the Polearm aptitude outclasses the unarmed combat aptitude due to the inherent reaching brand.
Reaching isn't much more than a single hit more vs most monsters, reduced for times when you are fighting more than one monster and they surround you/line up or stand in a corridor, because then you won't get an extra hit against every monster.
There are some cases where it does more, with summons, vs slow melee monsters (which are harmless anyway), with fast movement speed or cases where you attack past a monster, but this doesn't apply to most fights.
Looking at reaching as a damage bonus, then, it isn't enough to compensate for how higher the damage of forms + UC is (especially with Blade Hands), and Tm book guarantees you a venom branded attack and speed.