I worked on a project for a large SW company, and even though they had a simple pricing plan, one of their products wasn't taking off. But when we did some shopping and called in to their reps, none of them could clearly articulate why I would want to buy the higher tier product compared to the middle tier, and they even seemed the same on the website. The pricing was simple, but I had no idea what I would be getting in addition if I spent more money.
Contrast this to the iPad example, where I know exactly what I'm paying for. Every $100 increases my storage, and another $130 gets me 3G. It's very clear. I think cell phone plans are a great example of pricing that's complex, but easy to understand because the value is clearly communicated (every $X gets me X minutes). It's easier to make these decisions if I know what I'm paying for.