The point is, the first person stated that you can get a PC that is twice as powerful for half the price, that was a comparative statement (It does have twice the RAM, the slightly lower speed of the processor is offset by the much higher RAM. in practice, the computer will be faster. Of course you can't beat the speed of a SSD, but for a regular home user, this speed is more than enough

still no laptops for half the price that are more powerful

That is what you asked for and I that is what I gave you.

When I go from my air to a retina display I can notice the difference really easily, and the air is 13" and 1440x900

Of course you can tell the difference, again, for the average user, this doesn't matter. The Asus Zenbook is still 1600 x 900 for a 13" display. that is a higher resolution than 1440 x 900. It also seems that the viewing angles are better than the MBA (Yes, If my Laptop had a 1080p display it would be perfect, but it's not a huge difference, if you're curious, it is a ThinkPad x230t, so instead of 1080p, I have full multitouch, and a built in Wacom digitizer with pen- altogether more useful than a 1080p display, although that would be nice)

• The Asus has a longer battery life (See the testing on Engadget link)
• It is $200 cheaper (If you wait for a sale, getting it for $900 is possible making it $300 cheaper than the equivalent MBA which is $1200.
• It is 0.6 pounds lighter than the MBA
• it comes with VGA and Ethernet adapters and the packaging doubles as a case, for a MBA, you will have to pay extra for all these things (the adapters are $34 each, and lets say $15 for the case, that's roughly $70 in extras you get already)
• it also has mini HDMI and mini VGA, both widely used formats for sharing media. Thunderbolt is still rare
• This review is from 2011, the Keyboard was back-lit and the track pad much improved as of last year (friend has it, the track-pad is very good now)
• Speakers are engineered by Bang and Olufsen- still sounds like Laptop speakers, but warmer than most, but it gets pretty loud, and sounds good (Don't know how it sounds vs an MBA)
• Performance wise they are almost equal, here is a quote from Engadget: "If benchmarks are any indication, the UX31 matches -- and sometimes bests -- the Air's performance. In PCMark Vantage, for instance, it managed an impressive score of 10,218, compared with 9,484 for the Air. In 3DMark06 it notched 4,171, while the Air landed a similar score of 4,223."

Literally "Exactly double the power for exactly half the price", is a metaphor that you can get a machine much more suited for your uses for less than what Apple has. In fact an i3 may be too powerful for many users, realistically, you don't even need an i7 unless you edit video, game a lot, or use CAD. The fact is, If I were to buy an Ultrabook, I would choose the Asus, It's just better, and cheaper, and I can run Windows or Linux on it (I can't stand OSX, the easiness to use becomes frustrating when you have to do something slightly technical, and you can't)

EDIT: The Dell XPS 12 (not 13) has full multitouch, and a 1080p screen for the same price as an MBA, you can even get 8GB RAM, only draw back, it is 12 inches.... not a huge difference, but for this argument...