I had BOAs on a pair of Korkers and on a bunch of cycling shoes. They work well, but the mechanism can jam up with mud. I soured on them when I had one break way back in the bush. They can be replaced, but it's not something you want to do on the stream. Since then I've stuck to laces (and carry a spare).
I also have a pair of the river tractors and they have amazing traction. They are also incredibly heavy, not suited for walk and wade IMHO. The Simms alumabite system gives you almost as much traction without the weight