I've been happy for a couple of years with an earlier model Camelbak "Octane LR" - lightweight backback style with the lumbar (waist) bladder. They're designed for adventure running or something like that but I'm a fan of the lumbar/backpack style for SUP. Keeps the water weight down low on your hips but feels more secure (to me) than a bumbag type.
Tried on a Molokai recently and didn't like it much, it's got some good features but after the LR the water weight feels up too high. The bloke with the orange board in DJ's vid is wearing a Molokai over a PFD. PT has a Baja, I don't think he likes it but he'll be able to tell you why.
Yes I've had the Molokai for about 6 months. Very comfy and doesn't move about. Was also surprised that the weight of it full of water doesn't affect my lower back at all! Highly recommend!!!
I personally paddle with the VestPac Wilson Pac and love it. With the imminent arrival of the bigger 1.8l bladder I think it makes it more suited for any longer paddles also. It is light and the bladder is super easy to clean and there has never been any issues with the bladder tainting the water with any weird taste.