IPS: http://en.wikipedia.org/wiki/TFT_LCD#In-plane_switching_.28IPS.29
I'd prefer Apple utilize P-IPS.
It sure sounds good, but maybe there are practical considerations. Getting any form of IPS at all was a good improvement. A year ago, I thought that IPS was getting pushed out of the market because of cost.
Brighter and cheaper sounds good, but I wonder about power consumption. The viewing angle on the current iPad is good, I wonder how much better this display can get.
As for power, what you can do is dial it down, though I wonder if it raises the bottom end brightness by 10% or so too. I rarely set a display above half way in its adjustment range because it doesn't improve anything and starts to get fatiguing because it's too bright. Sometimes I use devices in relative darkness and wish I could turn it down even more than the slider lets me.