I have had the same issue no matter what adapter I have. Right now I'm using the belkin (which is pretty well reviewed here, after the "blue cube") with two keyboards on it. Every once in a white it'll reset, and I won't be able to type for a few seconds. This only occurs during use, and I don't know why. I don't think it's a power concern, as it still does it even with just one keyboard.
Other than that, it works great.
The best is probably the PI-engineering one, but it's like $50, or a soarer adapter, but you have to DIY to get it.