I recently used the Delaney in my first marathon after running with the belt just once before the race.  The temperature was in the low 80's for the bulk of the race.  Without the belt I'm sure I wouldn't have survived.  The belt is comfortable once you learn how to properly adjust it to the small of your back.  The additional liquid capacity comes in handy especially if you loose allot of water weight like I do when I run.  I have used other smaller belts but the capacity is just to low on longer runs.  I used the small gel flasks for water (to wash down the gels!) and the larger bottles for Gatorade.  The pouch held four gels and two cliff bars overall the capacity is great.