Legit Reviews posted a review on the ASUS ZENBOOK PRIME UX31A Ultrabook

The new ASUS Zenbook Prime UX31A might look exactly like the old Zenbook UX31E, but remember it is what is on the inside that really counts! ASUS appears to be all about consistency these days and have kept the sleek aluminum chassis the same on this razor thin Intel Ultrabook . The weight of this thin Ultrabook also remains the same, at 1.3 kg or about three pounds. It is only when you open the Zenbook Prime UX31A that you'll start to see the improvements over the last model. For example you have an illuminated keyboard with a gorgeous 1080p IPS (in-plane switching) display for you to look at when you use it and on the inside you have a 3rd Generation Intel Core i5 or i7 'Ivy Bridge' processor along with the new Intel HM76 Express chipset. The new processor is faster and also includes improved graphics thanks to the inclusion Intel HD Graphics 4000 technology. The new Intel HM76 Express Chipset brings native support for a pair of USB 3.0 ports, so both USB ports on the Zenbook Prime are SuperSpeed USB 3.0 enabled. ASUS didn't stop there though and fixed a number of smaller issues that end users griped about on the original Zenbook. For example the power connector easily came out on the Zenbook, so it was changed to a different type that 'clicks' in and stays in place on the Zenbook Prime. Basically, ASUS fixed what needed to be fixed and left what was working alone! This is great news for consumers as you get a refined product that has been tried and tested by millions of people.

  ASUS ZENBOOK PRIME UX31A Ultrabook Review