I prefer the small Donner bag (the Equipment Placer bag). It is very small, but holds all I need it to. It is only 9"x6", but seems to hold a ton. It has a pocket on the backside that holds park maps and my Hidden Mickey book, a zippered center section that holds my camera and 7"x5" notebook (with room left over), then the front has a velcro opening that folds down and the front part has a zipper compartment that holds a divider thingy that holds all my park ticket, ID, room key, credit cards, fast passes, and a little cash. Then it has four pockets above it. One is padded and holds my cell phone, there are two little ones that hold a hand sanitizer and a Tide Pen, then the biggest one holds my comb, a bottle of mixed meds, and a pkg of facial blotters. It's very small, but holds everything I need and has a long strap, so I can wear it cross body if I want to.
I've carried a WDW backpack, a Very Bradley backpack, the baggalini, a small leather back pack, a personalized Walt Disney messenger bag I bought at Walt Disney shopping.com, and multiple other bags down there. The Donner Equipment Place works better for me than any of them ever did.