I use them and I love them. I actually penny sleeve my cards (need to trim the top of the penny sleeve a little) and then put them into the pages. They fit nicely into the pages.
It's also more secure if you were using the binders for trading as it is more obvious to take the cards out than from the top load pages.
And you also don't have to worry about the cards coming loose and falling out if your binder happened to be turned upside down.