The Two-handed skill gains experience relative to the damage dealt by equipped two-handed weapons. The more damage that is dealt, the more experience is gained. There are 3 classes of weapons in this category.
Greatswords are the fastest, yet weakest of this category. Even though they are the weakest in the category, they still possess exceptional strength. They are ideal for knight and berserker classes, having enough speed to face well against an assassin or rogue, and enough power to down most of the weaker to average enemies in a single power attack.
Battleaxes are rank between Greatswords and Warhammers, having about 35-50% more strength than Greatswords and about 45-60% less speed. They are recommended for well-armored classes only, since their slow speed will make any lightly-armored class vulnerable to rogues and assassins.
Warhammers are the most powerful of all non-magical weapons. They are able to kill most any of the weak enemies in a single light attack, and most medium-strength enemies in one power attack. However they are the slowest weapon in the game, a dagger can get 4-6 attacks in during one warhammer swing. They are most fit for berserker classes because of their staggering damage, and only heavily armored classes will be able to withstand the inter-swing attacks dealt on them.
The slower the weapon, them more stamina it costs to perform a power attack. In short, two handed weapons, because of their slow but massive damage attacks, are most fit for either hard-hitting, high-stamina classes such as a berserker, or a well-armored, high-stamina class such as a knight.