Never used one at any distance. I think there are more than adequate aid stations to stay hydrated. Maybe look at the course map for where they are located, but I'd do almost anything not to have a pack on my back especially in that heat. Maybe consider carrying a handheld to supplement whatever aid stations there are if you feel the need for a quick drink somewhere in between.

Since looking at the map it looks like they are practically every mile, I wouldn't but to each their own. As another poster said, if you feel you need something I would do a handheld. In the heat that pack will get warm, and the extra weight (depending on how much you carry) could slow you down.

another vote here for a hand-held bottle. me, i ALWAYS run with a hand-held, even shorter runs. nice thing besides having a hit of water between aid stops is being able to give the head/face a cold splash when it's hot.