While some of my existing cases are too wedded to the iPad 2 form factor, my REV360 from Hub Innovations is fitting the bill nicely.
Retina quality apps are being approved daily and we will be able to appreciate the display more and more each day. Of course, as a developer, I had to try some of my own apps, and I happened to be using 300dpi images since the iPhone 4 came out, so thankfully apps like Ringtone Director Pro look nice on the new iPad. Of course built-in apps, including Safari take advantage of the screen.
The iPad itself is indeed faster and more responsive. Quick flicks left and right bring up different pages of icons faster than before. Even clicking and double clicking on the home button is more responsive.
I've read about, and experienced it myself, a hot spot and not the good kind. The corner to the left of the Home button gets warm with prolonged use. We will have to see if it becomes a bigger issue, like AntennaGate. For now, I'll hold the iPad with the home button on the left, if I need to use landscape mode.