Here are a couple of options I'm considering:
Nathan Speed 4R Waist Pack with Four 8-Ounce Nutrition Flasks
Nathan HPL #020 2.0 Liter Men's 2-Liter Hydration Race Vest
The vest is slightly more expensive and has more capacity than I really need. On the other hand, I'm not sure I really want to carry 32 oz on a belt. My current belt tends to slip with only 16oz, especially after about 7 or 8 miles.
Please let me know your opinion, especially if you have used one or both of these or similar. What are the pros/cons of each one?