The mount is starting to show up on live realms today. Some folks that have very deep pockets are picking them up for the maximum cost. Reactions are mixed. Most people will target the mount, look through the vendors, and some will ask to get on it for a quick ride. Others will /point /laugh.
The vendors on the mount are both a reagent vendor and a food / general goods vendor. The reagent vendor allows you to repair on the fly, the food / general vendor lets you pickup food and water when ever you need it, and both allow you to sell stuff on a whim. The general vendor also has unlimited arrows and bullets.
It's very nice for leveling in some ways, and will be quite nice for raiding in that you'll always have someplace close with reagents and other essentials.
But is it worth it?