I'm pretty sure I first learned about the Gripster from here. I got one a couple of months ago and I love it! I have used so many iPad holders before finding the Gripster, that I decided to write an article about it.
I also mentioned CoylCushions, which I also learned about from this forum. Another very nice product which I use daily.
If you know of something you think is better than Gripster, please, I beg you, DON'T tell me about it! Hahaha!