WOW, after looking at Rob Gailbraith's site one is completely confused. In regard to write speed from card to computer: it seems that card manufacturer, type, capacity and the card reader itself all have a greater impact on speed than the choice of USB 3 or USB 2. I'm baffled.
All that I can suggest if the information is that important to you, is to go over his site until it sinks in.
Most people aren't so diligent. They choose their cards based on the lowest price, what a friend tells them, some just buy the latest and greatest card at the best price.. which is mostly what I do, but I then run it buy Rob's site to make sure it doesn't have unexpected issues. Oh, and it must say Sandisk on it..
Some people believe it's better to have multiple smaller cards, in case one breaks they don't lose all their data, and others (like me) buys the biggest card available thinking the potential for loss with multiple small cards is much greater than cards going bad.
Just break it to the areas which are important to you and don't let a salesman influence you.