A few months ago I 'reviewed' the iLap and pointed out some problems I was having with it. I recently bought something similar, a Road Tools PodiumPad, and while it doesn't work very well as a "lap rest" (not that it was designed for that), it is perfect for raising the height of your notebook to a more comfortable reading/typing level. It's incredibly sturdy and there's no noticeable movement as you pound away at the keyboard.
The same rubber is used throughout (both on the bottom of the pad and on the parts that touch the bottom of your notebook) and it's very sticky — your notebook is not going to slide off. I mention this because the iLap would, depending on temperature, allow the PowerBook to slide right off the front of it; as the weather got colder the rubber feet on the bottom of the PowerBook became less apt to 'stick' to the aluminum iLap.
One very useful feature of the PodiumPad is that it can swivel 360°, which allows you to easily show others what you're looking at and to move the notebook slightly to the left or right as you change seating positions.
As odd as this may seem, I really have nothing negative to say about it. It would be nice if there was an attachment that you could use for your lap, but, outside of that, I'm pretty pleased.