Length is not always a good stat to have. Remember, the longer your weapon is, the more likely to glance at close range.
Length makes you slower.
Length usually means heavier, which makes you slower.
Length makes you glance.
However, common sense, you hit things from far.
Now, due to horses and teammates and all that nonsense, for direct battle (NA1, EU1, etc), A Long Awlpike is probably a safer choice. You can stab people before they notice you are there, and the fighting is more medium range oriented.
If you play siege, a regular awlpike is tons better then the long. You'll still glance at hug-range, but it is shorter, lighter, faster, and does more damage. (Players on siege lean toward heavy armor, high strength.) They are slower, but you don't have the mobility you get in battle due to walls. So despite them being slow as molasses, you'll still be in close range more often and you definitely want a short spear for that. Might even suggest battle fork...
In the end, you can use whatever whenever. It all works. These are just my experiences in the game and what I feel is more effective.