Grow Your Own Avocado: Dirt or Water?

I wanted to grow my own Avocado Tree. All the instructions I found online described suspending the pit in a glass of water with toothpicks. There was ONE website, that mentioned that planting it in dirt would lead to faster growth, but then she gave no instructions for planting, just for suspending in water! Anyway, I decided to try both ways and see what worked better.

I cut open an Avocado, being careful not to touch the pit with the blade of my knife or with the spoon that I used to pull it out of the center. I washed the pit off, poked it with 4 toothpicks and suspended it in water. A couple months later, this is what it looks like:

One nice root, but no leaves or anything else, yet.

 A couple of days AFTER suspending the above pit in water, I opened up a second Avocado. I burried it only half-way in the dirt, and set it on a west facing window sill. I water it daily, keeping the dirt fairly moist. Now, a couple of months later, this is what it looks like:

Apparently, dirt is better. Which makes sense. It's not like the pits get randomly suspended in water in nature, right?