My Father-in-Law fell for the marketing gimmick during last year's TdF (buy 3 get the 4th free) and gave me two. I don't think they are any easier to keep clean ... like Silvercivic said, "it's called a bottle brush ..." But the biggest down-side IMHO, is that the plastic is thicker than your regular bottle. This makes them harder to squeeze and it deforms more of the bottle when you do so it leaks from around the threads.

Bottom line, if you don't know how to wash a bottle and like your drink everywhere but your mouth, buy it!