I read that comment in many of the on-line reviews and the position of the ring around the ball for and the need to rotate it left / right to scroll up /down seemed much more awkward and counter-intuitive that just clicking both buttons of the orbit to scroll. That's one of the reasons I opted for another Orbit. More often than not I just use the up / down arrows on the KB to scroll web pages.
The thing is that I "need" more than two buttons, four is a minimum but I would be able to get by with three. And I didn't really get along well with the two-button-scroll. But to each his own.
I have two pretty expensive mice right now, and they are wonderful in features but they give me wrist pains. If I don't get used to them soon I will have to find something else.
I do use a Wacom Intuos for graphics work though and that's a relief, but it doesn't work as a mouse replacement when doing other things.
By the way, I noticed the old Studio Display in that picture. I didn't recognize it at first, but then I remembered that they made those for a short period. When was it? 7 years ago?
I've never seen one in real life though. I bet they are fairly rare these days?