Check this out. It's written by an "expert" who explains the IPS screen and how Apple made a "mistake" choosing it. The interesting thing to note is - this was written right after the keynote. The end of the article is priceless.
http://gcn.com/Articles/2010/01/28/FAQ-on-iPad-IPS-display.aspx?Page=1
http://gcn.com/Articles/2010/01/28/FAQ-on-iPad-IPS-display.aspx?Page=1